I've played rogue for seven years so that's what I recommend. Even though I haven't played a warlock since 2007 (SL/SL on the tournament realm, no words) that would be my alternative if rogue isn't to your liking. I've always found druids and shamans to be incredibly boring.

Don't go with rogue. I've been playing one going on 4 years now and they're not going to have a fun time in MoP. They're OP now, but we're getting a fairly large nerf in MoP. Not to mention the new rogue talent tree is really boring. ALso, many of the classes glaring problems aren't being addressed.

Druids are pretty fun, and you can play any role. Their forms get armor in MoP which will be a good change. I'd go with warlock though. Player's don't seem to like the shaman changes but warlocks have a sweet talent tree. I mean, they can cast, and move, changes everything.

@RedRoach: The fact that the forms have armor sells me pretty hard on druid.

@scalpel: On the other hand rogues hit a certain niche I like...

Troll shaman. 'Cause that's what I rolled back when WoW was relevant. :P

Demon Hunter

None of those are the ones you should play.

You need to be a Tauren, because who doesn't want to be a Miniature.

@Breadfan: Already played that, didn't like all the abilities, rapid fire was fun.

@Dagbiker: Tauren Shaman and Druid are definitely possibilities. Too bad I can't be a Tauren Rogue cause the hilarity would sell me on it instantly.