Newcomer (first level perk): You suddenly find a fishy stick in your back pack, useful for surviving during dungeon crawling.

If they're going with the whole "perk tree"-thing some of us have expected, I can see something similar to this being used.

Block at 25: you get a choice between two perks. One gives you a bonus while blocking with a shield, the other gives you a bones while blocking with a weapon. The more your skill increases, the more you can upgrade the perks you already have, or select new ones if you so desire. A 'tree' could then be something like this:

Block: Shield Expertise -> Block: Shield Protection -> Block: Shield Bash
(with fancier names, though)

Later on, you could tie certain perks to more than one skill. For instance, if you've got both Block and Blade at 75, and have leveled up your Shield and Long Blade perks, you could gain a special "critical strike"-move that allows you to deal critical damage to an opponent who got staggered by your Shield Bash.

Short Blade perks could give you "backstab" and "flurry" abilities, for instance, when coupled with sneak and combat, respectively.

There's endless possibilities for a system like this. If Bethesda's is different, I'll be remembering it for the time when I get to make games someday, if ever. Keep 'em coming guys.

Battlemage perk tree:
Battlemage – Channeling offensive magic through armor have increased you efficiency with Destruction magic. When wearing armor your Destruction spells is not affected by spell efficiency. Require Destruction 50, Heavy or Light armor 50 and lvl 20
Expert Battlemage – You have become a feared foe on the battlefield, wielding steel and magic better than most. When wearing armor all Destruction is not affected by spell efficiency and damage resistance is increased by 5%.Require Destruction 70, Heavy or Light armor 70 and lvl 35
Master Battlemage - You have become a feared foe on the battlefield, wielding steel and magic better than all others. When wearing armor all Destruction spells ignore 20% of resistance(magic/elemental) and damage resistance is increased by 10%. Require Destruction 90, Heavy or Light armor 90 and lvl 50

Mage perk tree
Mage – Studying the arcane art have increased your efficiency with them. All spells are now 10% more effective. Require all magic skills at 20
Wizard – Studying the arcane arts have increased your efficiency with them. All spells are now 15% more effective and your magica regeneration have increased. Require all magic skills at 50 and lvl 25.
Arch-Mage - Studying the arcane arts have increased your efficiency with them. All spells are now 20% more effective and your magica regeneration have increased substantially. Require all magic skills at 70 and lvl 40.

Just a few I'd want for my own reasons:

Note that the mechanics given are because the effect needs to "at will", rather than "constant effect".

Dash- gives you a spell that, when equipped, tripels sprint speed, but burns magicka right alongside fatigue. cannot be used for 1 hour if run to exhaustion. potion duration and effect are halved relative to standard sprinting.

Turbo- sprint speed is increased to 7x standard, magicka and fatigue burnoff is doubled. Cannot jump, fall speed doubled. Cannot attack or cast spells.

Trial by *: gives 10% innate resistance to whatever the effect is.

Redirect Edge- when using any blade that may be used two-handed, a timed block will catch hostile spells. Holding a spell burns magicka proportionally to strength of spell. Attack w/o block to release, or attack with block to use the spell as a temporary enchantment (not usually a good idea).

These may or may not be game-breaking. It's for entirely "strange" reasons...

These are great! A nice middle way between classes and the classless system !

Thanks
I am creating a series of these now. I have Crusader, Necromancer, Battlemage and mage posted so far(all in this thread). Warrior and some stealth are coming

Book worm - Skill books give you twice the skill increase.
Ladies man - Female NPCs like you twice as much as before. (if male)
Look at my horse, my horse is amazing - Horses you own can now fly, sing and taste just like raisins.
Master of intimidation - NPCs and creatures are twice as likely to retreat from battle.
Use the force - Once a day you can levitate objects for 60 seconds.
Winter wonderland - Dragons will now appear as giant flying snowmen.

Warrior perk tree
Warrior – Usage of the melee tools have left you with a know-how few others have. All weapons and armor are now 10% more effective. Require lvl 15 and all melee skills at 20.
Fighter - Usage of the melee tools have left you with a know-how few better than most of your equals. All weapons and armor are now 15% more effective and you have an increased fatigue regeneration. Require all melee skills at 50 and lvl 25.
Champion – Your mastering of the melee tools go beyond that of everyone around you. All weapons and armor are now 25% more effective and you have an substantial increased fatigue regeneration. Require all melee skills at 90 and lvl 40.

Stendarr's Hammer - Warhammers does 30 % extra damage and ingnores some armor rating
The Great Juggler - Dual dagger throwing
Vital Stabber - Damage against an enemies torso does 25 % more damage

People said "mounted combat is unfair" but using the same weapon as your opponent yet dealing %30 more damage is much more unfair if you ask me.Not that I care for balance between NPCs and players in a single player game,but still.

I also find the percentage stuff boring.It'd be better to gain something more fun and unique after waiting for a level.

Shield bashes paralyzing,blunt weapons crushing armor,multiple arrow draws etc. are things that I like more.

I'd like a perk that makes it possible to pin a NPC to a wall with an arrow if he's close enough.For 5 secons maybe,if survived.

Assassin perk tree
Assassin – Stealth and shadow is your ally and hides your sinister intentions. Sneak-attacks are 15% more effective. Require Sneak 40 and lvl 15.
Silent Murderer - Stealth and shadow is your ally and hides your sinister intentions, and poisons are now your favorite tool.. Sneak-attacks and poisons are now 25% more effective. Require sneak 70, alchemy 50 and lvl 35.
Master Assassin - Stealth and shadow is your ally and hides your sinister intentions, and poisons are your mastery. Sneak-attacks now ignore the targets armor and poisons now ignore 20% of resistance. Require sneak 90, alchemy 70 and lvl 50.

Spell Rebound: If hit by a spell that causes a certain amount of damage, your next attack will include the same spell on top of your attack.

For example: The minimum damage for this perk to activate is 30 A mage hits you with a fireball dealing 50 damage, your next attack (regardless of spell, sword or marksman) will have a fire spell hitting 20 on top of your attack.

I hope thats clear enough..

Hunters Intimidation: Kill 50 of each creature within Skyrim and they will all be non-aggressive towards you and even aid you in combat, if attacked they will flee.

Crossblade: Gain a high enough skill in Blade and when dual wielding swords you will be able to disarm your opponent if they are also wielding a sword in combat.

Achilles Heel: In combat if you are using a spear you will deal double your damage if you hit your opponents legs.

Tactical Bulwark: When shield bashing an enemy you will have a chance for them to drop their shield/weapon as well as knocking off any helmet they might be wearing; coinciding with the ability to hit 25% stronger after this has happened.

This might be humorous .

Ranger perk tree
Ranger – Bows and light armored combat is your specialization. Bows have 10% more damage and light armor provides 5% more damage resistance. Require Marksman 35, light armor 35 and lvl 10.
Expert Ranger - Bows and light armored combat is your mastery. Bows have 25% more damage and light armor provide 20% more damage resistance. Require Marksman 50, Light armor 50 and lvl 25.
Legendary Ranger – You are now a legend with bow and light armor. Bows have 35% more damage and light armor provide 30% more damage resistance. Require Marksman 75, Light armor 75 and lvl 40.

To collect my ideas in one place.

Just thought of a small one:

Dirty fighting: your sneak attacks have one of these effects on the target, (high chance) crippling, silencing, knocking down. (low chance) Paralyzing, additional double dmg

I've taken your critiecs into consideration. I took out plague bearer and changed teleport to "Fast Travel" however "mercy" isn't meant to be useful. It's meant to be an RP thing. For instance your character might not like to kill people only monsters with this perk they'd be able to keep their character aligned like that. I'm still in the process of updating my perk list so it will probably be posted within the hour.

Fimmionism: Eating a sweetroll will heal you as much as a Strong Healing potion.

Man of steel - When wearing steel armor, you take 50% less damage.
Smarter than the average bear - Bears are no longer hostile towards you and may even assist you in battle.

Cheese for everyone!!! :Eating cheese gives you a increases your damage with all weapons and magic, and you don't lose fatigue while sprinting.

M'aiqs Intuition: Listen to all of M'aiqs unique dialogue and you will gain 10 points to Speed and Speechcraft. After gaining this perk, if you give M'aiq a Colovian Fur Helm and an elusive Fishy Stick the perk will upgrade to give you 25 points instead of 10

Oh my god, people are taking this seriously, ok then, speechcraft :
Whistling nonchalantly : Bounty level before guards attack increased due to the innocent looking way you have of walking away with your hands in your pockets
Check the size of them babies : Hostile NPCs momentarily stunned as you heave your bosom or they catch sight of your ...you know...package.
The fine art of blagging : Merchants give you a decent price for tan cups.
You looking at me? : NPC disposition increased as you win staring contest. Don't try on the wrong guy unless a fan of that perennial favourite, the Bar Room Brawl.
OOH love your nails, they go so well with your blue skin : Disposition of Dunmer increased.
Brown nosing : Disposition increase and extra speech options when fawning over Nobility.

This is an updated version of my later post after considering even more posted perks.

These are the perks that I think are viable, some I've tweaked and I noted my tweaks.
I would like to add that I do HOPE Strongly that they don't transfer FO3 or NV perks over. I would like them to stay more in line with oblivion.

also I do not believe in a tech tree Or active skills, only passive skills.

Magical Restoration - Enchanted items recharge over time.

Royalty - Allows you to wear an extra ring or amulet (plus generally higher disposition)

Extended summons: Your summoning spells last longer then normal.

Backstabber: 15% extra damage on a backstab

Now or Never - When health is under 10%, damage delt increases 35% (I changed the posted 75 to 35 which I think is more reasonable.)

Gifted Healer = Restoration spells cost 10% less to cast

Crusader = Gives 5% more damage against undead and vampires

Blood Mage: the lower your health, the faster your magica refills. (I changed the name from the original post which was "Dark Magics")

Burglar: At night you gain a bonus to stealth and security.

Mercy - instead of a fatal finishing move, you can opt to knock your enemy unconscious when they run out of health. But you can still pick-pocket them and leave them in their underwear

Fast Travel - a justification for fast travel, and making it an early perk would act to make it optional as well (changed the name from teleport to fast travel figured might as well call it what it is. Thanks for the suggestion Skaevola)

Strong Minded = Allows you to shrug of lesser mind affecting spells and effects

Charming Voice - People are 10% more positive when talking to you (I changed it to 10%, 25% is to great a boost)

Deft Hands: Lockpicks break only after two unsuccessful lockpick attempts.

Natural Immunity - Minor disease effects are reduced by 35%, major diseases are reduced by 25% (I changed the minor disease immunity to 35% it was 50%)

Bar Brawler: Hand to hand increases when under the influence of alcohol.

Master Monk: while unarmed, you have a 70% chance to catch enemy arrows fired at you while you are standing still.

Trollblood: slow hp regen over time but with lowered resistance to fire

Juggernaut: Extra defense rating while wearing full heavy armor and shield, impossible to knockdown while blocking (heavy armor)

Meticulous Measurements - You are very meticulous when measuring the amount of ingrediants for your alchemy, you some times end up with a little extra. Every time when you create potions there is a % chance that you will recieve an ingrediant from the current potion back. The chances of recieving extra or even more increase with the complexity of ingrediants used. ( I would change it to "you only use half the ingrediants most would use")

Steadfast - Your fatigue now goes down 20% slower than before. High endurance/high athletics if their still their.

Master summoner: ability to summon certain creatures until their death.

Battlemage: wearing armor has less of an impact on the power of your spells. In addition, being hit with enchanted weapons now replenishes some magicka.

Brethren!: Shopkeepers of the same race will give a modest discount, same race NPC's get a mild disposition bonus, etc.

Vantage Striking: Your first attack after breaking invisibility does 25% more damage.

Magical Tracking: Detect Life and Night-Eye now highlight recent footsteps. (changed the name from sharp eye)

Aggression - If health falls below 25%, damage is increased by 20%.

Sprinter - Sprinting uses 20% less stamina.

Blademaster: Your practiced hand has no trouble tracing an icy trail through the air with the tip of a blade. You slice through your opponents defenses in the blink of an eye, thanks to your greatly accelerated attack while using a sword.(I would translate this to mean 5% increase in attack speed and 20% chance for piercing damage for all blade weapons)

Cleaving Swings: Your twohanded weapon swings can hit 2 additional opponents if they are in the weapons path. Deals 30% weapon damage.

Overwhelming Force: Your twohanded weapon swings have a chance to knock the enemy down. Chance increased for power-attacks.

Rushing Pulverizer: Your forward power-attack with twohanded weapons will propel you faster, do 20% more damage, and cause 40% splash damage to 2 close opponents. (this needs a name change haven't thought of one though)

Botanist: Increases the chances of successfully harvesting alchemical ingredients.

Mighty Archer: Increases bow damage by 15%.

Swift Archer: Increases bow speed by 15%.

Potions Master: Increases effectiveness of alchemical equipment (Alembic, Retort, Calcinator, etc.).

Spell Rebound: If hit by a spell that causes a certain amount of damage, your next attack will include the same spell on top of your attack. 10% chance of activating

Wizard - While duel-wielding the same spell, spells are 10% more effective and take less time to cast (I changed it from any spells to the same spells)

Arch-Wizard - Decreses spell cost by 5% more, and increases all magical resistances by 5% (changed Increase spell effectiveness by 5% more)

Spellsword - While a magical effect is active on an enemy, one-handed weapon damage is increase by 15%

No idea what to call this perk: Climb walls and stuff like in Assassin's Creed.