I'm sure most people will play through the game multiple times but what class will you use for your first playthrough (whether its an old save file  from ME1 or a whole new game) ? I really enjoyed the Sentinel playstyle from the first game with all the biotic absorbs and tech shields. So I'm glad BioWare made the Sentinel even tougher this time around.

The Adept looks like a really beast class and if I can role with Wrex again then I'll be set. :)

Sentinel

I'll probably go for engineer, but Infiltrator looks appealing too. 
Edit: They're all tied at one vote apiece.

I have a 60 adept from Mass Effect, so I'll likely transfer him over first.

I played ME as a Soldier, I'm going to play ME2 as a Soldier.

I'll play as a soldier. I'd rather have a larger array of weapons than force powers. 

I'm carrying my Mass Effect save over to the sequel, so, Vanguard :)

Wrex is in the game if he survived  the first, but not as a squad-mate. 
 
ITT:
 
Soldier for me.

Its looking like Infiltrator.

Between Adept and Vanguard, I am unsure right now though,

Soilder, I went with infiltrator last time, it was horrible. I don't need any specialities.

Going with Infiltrator. I really enjoy the using AI Hacking as well as mastering the sniper rifle. Plus the new cloak ability looks pretty awesome. Second play through, probably with either do Vanguard or Soldier.

Vanguard first for my male Shep, then Infiltrator for my female one.

Turd Burglar, but it seems it didn't make the list. So Vanguard.

Vanguard. My first Shepard from Mass Effect 1 was a Vanguard so I'm starting off with that.

I'm importing my Soldier from the first game.

" I played ME as a Soldier, I'm going to play ME2 as a Soldier. "

" I'm importing my Soldier from the first game. "

I have no idea. Leaning towards engineer,  but i guess i'll see what i turn my former adept into when the time comes.

" Turd Burglar, but it seems it didn't make the list. So Vanguard. "

" @pornstorestiffi said:

" Turd Burglar, but it seems it didn't make the list. So Vanguard. "

No thats going to be DLC "

Either Engineer or Sentinel.

I'll play my soldier from the old savefile..

I played an engineer in Mass Effect so I'll be importing him over for Mass Effect 2.

Soilder,I played as the adept and engineer in the original ME and I remember it taking like 6 days for me to kill an enemy with my weapons and never really using my tech,biotic powers so Soilder seem's like the class for me.

im pretty sure you can bring over your previous save and still choose a different class.. either way ill be an engineer or an infiltrator.

My Main save from ME 1 was a soldier so I'll play that first. After I want to try the Adept, the powers look badass!

I played as a Vanguard on the first ME so I'll do it again.

" Soilder,I played as the adept and engineer in the original ME and I remember it taking like 6 days for me to kill an enemy with my weapons and never really using my tech,biotic powers so Soilder seem's like the class for me. "

Sentinel. I found the soldier class a bit too stale for my taste. 

I have a soldier and a vanguard in the can already and I am starting (wow 3rd run!) an adept in ME1 so when I start ME2 I can choose.  I fumbled through the first time with my vanguard and steamrolled through a 2nd run with a soldier.  Soldiers are fast killing machines, but I missed the skills.  I was thinking of a sentinel, but one thing I did learn from playing a soldier is it's better to have class focus as opposed to being a jack-of-many-trades. 
 
So, when ME 2 drops, I'll probably start with my highest level character who ever that is.  Right now it's my soldier, but by the time the game is released it might be a different one.  I know that....

Adept since with soldior it is just......a shooter, and tech is well boring and pointless on half of the enemies

Played soldier and vanguard in ME, probably will start with vanguard in ME2 even tho I liked soldier more. Hopefully soldier isn't as OP in ME2.

I am gonna run with a Biotic pure on my second replay I am a sucker for being a badass with guns and heavy armor but the Biotic classes look insanely fun and I can't wait to try it.
 
Edit: Shit I just remembered that my hard drive with my original save was stolen (broad daylight in a parking lot) so I need to replay before two comes out, Damn.

I played as a soldier in ME1, but I want to play using some powers the next time around, so I think I'll be trying a Vanguard this time.

Soldier/Warrior classes are what i start any RPG with. 

" Adept since with soldior it is just......a shooter, and tech is well boring and pointless on half of the enemies "

I will probably go with the Inlfiltrator this time to check out the newest (and oldest) tech powers, as the newcoming Tactical Cloak, and to use long-distance weapons. If I recall correctly, I played with a Vanguard in Mass Effect, as I was interested in trying biotic powers for once but also needed some firepower.