Hmm I've been looking at Red Dead Redemption actually, is it any good?
RDR is pretty awesome, definitely a must own if you're into Westerns. Though the auto aim is a bit wonky, you get used to it after a while. You can also slow down time which helps you out quite a bit.
Batman Arkham Asylum is another good one. Either of these will preoccupy you for a while. Or you cantake the budget route and get Infamous for $20 on Amazon, although there isn't an auto aim feature on that one...