This is not about what DLC I whant but what an expansion should/could include.

1 - Character creation.
More hairstyles (especially for females) and beard styles.
More scars (ones that cover the hole face and some that will apear on the body, back and front).
Presets for jaws, chin and cheeks.
More war paints with some that will cover the body.
Body hair choice from bold to curly.
Dirt to be on body aswell.
More presets characters.

2 - Magic spells.
Fire, ice and sparks sphere spell that can be charged to full power and will couse as much damage as the amount of magika you have or anything up to that (300 magika = 300 damage whene fully charged max) dual casting will ad 20% damage bonus.
Bound armour (over robes).
Bound two-handed sword.
Bound mace.
Conjure bear familiar.
Conjure saber cat familiar.
Conjure spider familiar (one hand cast = small spider, dual cast = big spider).
Conjure dog familiar.
Conjure Dragon familiar (just an idea .

3 - Weapons and armour.
http://media.80stees.com/images/products/Movie-Thor-Hammer.jpg.
Ancient Nord armour.
Forge your own staffs and enchant them (meaning lean enchantments from staffs).
Dragon skyforge weapons (all including bow, staffs).
Cross bows.
Throwing weapons (spears, knives, axe).
Use other objects as weapons (or atleast Pitchfork, Shovel, Broom).

4 - Patches.
Instead of just releasing apatch that will allow the DLC to fit the curent game make a patch that will also fix many of the other problems that will still exist in the game and are not related to the DLC the patch was made for.

5 - Enchanting.
Remove enchantments from you own made weapons and armour (at a price) to allow for different enchantments.
Soul gem mine where you can get uncut gems both normal and black and also a new type that will allow you to contain a Dragons soul, once you have unloked all shout, and you will be able to enchant with one that will have x10 the power of a grand soul.
Forge your own staffs and enchant them (meaning lean enchantments from staffs).
Enchant Invisibility.

6 - Other.
Equip lanters and place them with candles.
Permanet Mage lights to illuminate homes.
Use other objects as weapons (or at least just Pitchforks, Shovels, Brooms).
Teleportation pads to travel from inside all your homes (can be bought as part of home decorations).
Maps to give persentage of compleation for locations incase you mised something.
A colectable comperable to Fallout 3s bobbleheads.

Any sugestions?

How about more colors for War paints? That'd be a good start.

Hell, why not just the old RGB huh? WHY, OH WHY WAS RGB REMOVED????

New (old) skills. Unarmed and unarmoured for starters. The second of those might help mages a bit.

Spell crafting. Possibly as a skill?

New monsters. Including some unique ones. Like Udey's mom from Oblivion.

More variables for Radiant story/quest/AI

I'd like a house with a library big enough to fit all of these awesome books I've collected.

Spell crafting, horse armor and a castle. The castle would especially make me happy. It'd be super expensive, but it'd come with tons of upgrades such as a stable, servant staff, crops and defenses. Maybe you could even have an option where bandit raiding parties attack your castle every couple days or so.

Character slots!!

http://www.gamesas.com/index.php?/topic/1288090-character-slots/page__p__19427757__fromsearch__1#entry19427757

yes, I'm willing to start a viral campaign until I get them, hehe

I would ask for these:

1. Being able to create your own race, with hundreds of features to choose from, including: Hair styles, body types, markings, skin types, height and weight, voices, scars, gender, starting stats.
2. Being able to customizing your own weapons, changing things like: Hilts, scabbards, the blade style, width and length, guards, engravings and decorative features like, jewels. Changing the colour of the hilts, and giving the blade a tint of any colour you choose.
3. Being able to take combat to an all new level, giving the player new moves like: counter attacks, throwing an enemy in a chosen direction, silent kills, disarming, suffering real injuries that impede combat.
4. Being able to make a positive or negative impression during the game, stuff like: having a good reputation or bad one, leading your own bandit group, claiming a old ruin, fort or castle for yourself and taking control of the land or doing the opposite and battling for the people of the world as you play through the game.
5. The crime and punishment need to change, such as: spending actual days or weeks in prison, having to survive harsh sentencing, escaping using any method you can think of such as: pick lock the door (so old) or start a prison riot of sorts, dig your way out using stolen tools (might take days to finish)
6. Having to maintain your armour in game, seeing visible wear and tear from constant combat. weapons can break but remain in inventory until fixed.
7. Cloaks that aren't pinned to the characters knees and have a life of their own as they flap in the wind or can be used as a protection against cold weather or conceal weapons and stolen goods.
8. A vast open world that not on has lets say Skyrim, but all of tamriel for the player to explore with places such as: tundras, volcanic wastes, marshes, swamps, open plains, vast river networks to make use of small boats that the player can use to travel across the games map more quickly rather than horses or walking/ running.