I know TES allows for Battlemages. Not sure how they work, but I picture a warrior in plate gear casting spells at range and swinging a sword/mace up close.

For a battlemage type character and also for straight mages, how does armor affect them casting? Are there any drawbacks, ie longer cast times, less mana, etc?

I don't think there are any penalties for wearing armor and casting spells like there was in Oblivion. I am using a light-armor wearing spell caster and having fun doing it. Go for it.

There isn't any penalty for casting spells in heavy armor, BUT the mage robes and hoods give extra magicka regeneration as well as extra magicka overall. Lately I've been running around in steel armor, but with a novice hood on, I never seem to be too low on magicka.

I don't think there are any negatives other than the allowable enchants on specific pieces of gear. It's kind of screwed up, really. The main draw to mage robes is for the magicka regen which doesn't work in combat.

On the plus side for wearing armor, you get to survive melee encounters more easily because you take less damage.

On the down side, though, wearing armor and casting spells might make you a little TOO awesome. (It's an issue.)

I wear a mage hood in light armor. The hood give me a little extra juice. In fights against more than two others, I usually run out and have to drink a potion or use my swords.

Magica regen gear doesn't work in combat?! I havent tried a magic user yet. And after reading that i dont think i ever will. Sounds like a potion spamming fest, if you try to dish out damage and protect yourself at the same time.

I got my smithing to 100 and made full heavy dragon bone armor and enchanted the pieces availible with -20% destruction cost (enchanting not maxed). Now my destruction casts at 20% (maybe 10% due to perks) cost so I never have mana issues even spamming my highest tier spell and I can actually take a few hits from a pissed off dude with a big sword.

The only negative that I have noticed is that I can't sprint for as long a period of time and I think I move slower as well, but I haven't tested the movement thing yet. I haven't noticed any difference at all from having +100% magicka regen with robes and -50% with heavy armor and atronach stone buff, so something isn't working correctly with magicka regen. For me it makes the choice a no-brainer. If magicka regen worked correctly in combat it might be more of a toss-up.

It does, but in combat it's only 33% your regen rate from gear. All mages have to stack enchanted cost reduction gear at high levels in order to be able to put out the damage required to kill things and, like you said, not have to spam potions the whole time.

You dont have to wear armor as a Battlemage. Just dual-cast Destruction spells and get the 3 mage armor perks from Alteration.

The only penalty I see in wearing armor and using magic is that your magicka regenerates a little more slowly than if you weren't wearing any armor.

However, wearing armor+casting mage armor is great defense.

You'll move slower.

Also, regarding Alchemy, remember that it is now associated with the Stealth school of skills rather than Magic school.

You move faster without armor and stamina replenishes faster. Also there's an alteration perk that makes Mage Armor (oakflesh, Ironflesh, etc..) a lot better as long as you don't wear any armor.

So if im wearing only robes and i had an item that gave me 100% faster mana regen. I would get 33% faster mana regen in combat?