Mostly WoW at the moment, but I need to go back and finish HL2, GTA:SA (just a couple missions to go!), and Metroid Prime 2. Not to mention PoP which I got over Black Friday.
HL2 would be out of my backlog by now if it wasn't for the fact that I had to reformat my HD and lost the saves (I transferred the game to my secondary HD). I'll get to it eventually, though.