I'll be using my conjuration sorcerer.

Buffy Summers, the vampire Slayer. Pulled off Earth plane and incarnated on Nirn as a Dragonborn Nord. I act as her Watcher and send her on vampire-hunting quests using the Prima guide to find their lairs.

She's a typical 1H/shield character with a sword emphasis (Dawnbreaker, naturally, but also an unenchanted scimitar for using with Elemental Fury). Uses the Lady Stone exclusively to represent her Slayer healing ability. I'm going to perk archery more so she can use the crossbow to good effect. No magic except enchanting. Doesn't do "evil" quests. She's a werewolf, but I will dewolf her before Dawnguard so that she has the threat of vampirism hanging over her. Actually I'm going to totally restart her after the 1.6 patch, since she's gotten a bit glitched.

I will probably resurrect my Dunmer spellsword as well. I ran into a lot of vampires with her, had a lot of tough fights. She specialized in fire Destruction, which is perfect.

I have quite a few characters that would be willing to join the Dawnguard but far less that would consider joining the Vampires.

My Imperial Paladin, my Breton Sacred Fist (Monk/Cleric), my Altmer Spellsword, my Bosmer Arcane Archer, and my Nord Barbarian will all join the ranks of the Dawnguard for certain.

My Daedra-conjuring Breton Warlock and Dunmer Assassin would consider both sides and would be willing to join the Vamps if turning is not necessary. Otherwise, they'll be among the more ruthless members of the Dawnguard.

I'll have my Necromancer become a vampire lord for certain though, maybe others eventually though I'm not normally fond of vampire or werewolf characters. If Lich was an option though, that'd be my preference for my Necromancer .

Wait so your Redguard is a spell sword, but your Dunmer is a pure warrior?

That's interesting. I kind of like it.

I will use whatever character I happen to have going when it releases. Most likely I will have my first run with my Nord Crusader Tynon, but it is not set in stone.

Level 80 dark elf mage. Werewolf...for now.

i plan on using my nord warrior in the dawnguard, as for the vamps i will probably use my dunmer mage as he looks evil enough as it is.

Eugh, level 47 (thought he was 49, but then I rolled back a couple of saves due to a bug) Dumner Assassin, who's given up the ways of the wolf in order to embrace those of Vampire.

As for my Dawnguard playthrough, my level 14 Breton (who I've painstakingly made look like me) ranger, who has the beast blood flowing through him (albeit more because I find diseases annoying more than actually using his wolf form), who I'm currently leveling up.

I somewhat despise undead (Meridia=win) honestly, so it's fairly obvious.

Full daedric, Daedric sword, and conjuration to the max, with a tad bit of marksmanship. I do enjoy killing with arrows.

I hope crossbows make my day.

I'm going to use my imperial archer vampire/werewolf (split save so one's a vamp and the other is a werewolf) first then probably going to use my nord warrior werewolf after.

my nighthaunter; main skills are conjuration, archery, enchanting and sneak. hes a vampire.

My level 39 Vampire Breton nightblade who leans toward necromancy, illusion, sneak, and one-handed and my level 15 Werewolf Imperial warrior who uses mostly bow and war axes with some sneak thrown in for the thrill of the hunt!!! I can't wait for the new additions to both vampire and werewolf!!

I am going to us my nord warrior, since cutting up vampires with a sword sounds good enough for me.

i'm going to create a khajiit vampwolf (vampire-werewolf combo, created by using console commands to remove the disease resistance effect given by lycanthropy) for the volkihar side, and my signature's high elf for the Dawnguard.

I made 2 Dark Elf Vampire Hunters and one of them has been fascinated with immortality and he will be easily seduced into siding with the Vampires and the other will have to join the Dawnguard in order to hunt him down....

My bosmer who is going to rain arrows and bolts on any vampire who stands in my way and if the get to close use my skyforge steel sword and spellbreaker!!!!

My female Nord, she's a thief/ assassin. A bad ass at that too

using my Nord first cause he is my fav character i have made so far...rockin that steel plate armor into the soul cairn

To join the dawnguard, standard Nord. Heavy/light armor mix, One-Handed, Block. For the vampire side, High Elf battlemage. Mastery of all schools of magic, light armor, and one-handed.

Female High Elf: Magic user/Werewolf

Female Wood Elf: Stealth/Vampire

Male Imperial: Heavy Armor/Two-handed combat/Werewolf

My good Orc who uses: Destruction, Alteration, restoration. And a bow so the crossbow will be great. Enchanting and smithing. Finally 1H.

as always, pure mage or a mage armed with a heavy mace and possibly heavy armor.