I do also play few other games, but I tend to stick with MMO's (Tribes: Ascend, Planetside 2, WoW (Have played GW2, SWTOR and Rift)
I just like MMO's more I think, changes the whole feeling of just sitting alone in some room. I do know I still sit alone when I play an MMO, but there seem to be a bit more interaction with people and the likes.