I hate it when people say they hate CoD and it sucks but they don't have a clue what they're talking about.
Honestly, only IW Call of Duties suck. Treyarch ones are actually good. The difference from each one is pretty awesome and it isn't as gimmicky as IW. So I'm not even going to say that is my guilty pleasure, unless I'm buying an IW one, which is so not happening after MW3.
I MIGHT have to say Assassin's Creed. I've been playing since the first one and I feel like all the games have just gone downhill from there, ESPECIALLY Revelations. That game sucked so badly. Hopefully AC3 will undo that.