All three of my teams' DPS are heavy AOE and I would have trouble playing any other way at this point ... warlocks (3), mages(3), druids (all five).

I'm most happy with the warlocks, especially with a pally tank, for burning down mobs with Seed of Corruption. All three groups hit massively hard with their AOE and so the differences between their actual damage delivered against normal mobs isn't too relevant -- mobs just die, period. The deciding factor for me is that SoC is ranged, and can help round mobs up. If the puller (usually my pally tank) gets knocked off her mount while rounding up, that'd be the end up of it if SoC didn't allow you to target outside of your little corral and add a straggler or two to the carnage. SoC is the only ranged AOE I can think of that doesn't require you to target the ground -- you just add it to a macro, everyone casts on a mob and stuff starts exploding -- so it's especially good for multiboxing. Finally, the locks have nigh-infinite mana, especially with imps and Dark Pact, and can keep grinding forever without having to stop.

The con, of course, is that you don't get SoC for a LONG time. I used Hellfire while leveling. Meh. I'd level warlocks again if I had to do it over though, it's worth a bit of RAF Rain of Fire and Hellfire to get to the SoC goodness.

My druids are my second favorite AOE team. I love the gigantic radius of Starfall. I mostly rely on Hurricane and Typhoon, obviously ... I don't mind mousing over to the other four WoWs to cast Hurricane on the ground, because I know a Typhoon is going to finish the burning-down and I'm 99% sure there won't be any stragglers beating on me. It's efficient and a pretty fun experience. The drawback with the droods is that I can't round up as big a group as I'd like, because when I'm mounted, I'm wearing crappy leather armor and subject to massive pummeling between being unhorsed and killing the last mob. They also have relatively crappy mana consumption, and Innervate doesn't help as much as I'd like.

My mages hit very hard, and their CC makes them just freaking insanely awesome in most instances. They're my third-favorite AOE team, and honestly I'm having trouble explaining why. They don't have any wild negatives that aren't shared by teams I like more (druids also gobble mana, and warlocks also wear cloth), I guess they're just slightly mediocre in ways that are important to me. That Arcane Explosion is a point-blank spell and the tank has to do more precise rounding-up is probably a factor. Maybe it's that they remind me of the locks, but don't have the huge virtual mana pools to draw from. I'm'a go with that.

So if I had to recommend any team at all, I'd say warlocks are you friends. Based on what you wanna do already, probably go with druids. They're incredibly versatile and just plain fun to play.