mine would be batman :arkham asylum

Assassin's Creed 2 which is also my 2nd favourite game of this generation.

Borderlands

Forza 3 all the way. It's my favourite sim racer this gen so far ;)

I went Assassins Creed 2, its pretty much a masterpiece. Batman AA was awesome too, in fairness that entire list is very good.

Batman Arkham Asylum ftw

Outside that list my Favorite 360 game of all time is Mass Effect 2, I was at the game store yesterday and they has AC2 new on sale for 19.99 , I was going to buy and the employee said it was one of the worst games ever, I really did not know much about it, just a few friends really liked it, so I bought MW1, and World at War, on PS3, both new for a total of 40 bucks, which are games I already had and beat buy traded in like a dumb ass, so I wanted to rebuy them, but not bad 40 bucks for both, I want the new Ratchett and Clank , for my son, and Batman, so I will buy them next, oh and AC2 I may give a chance, if anyone has some input for me, please message me, thanks

MW2 I guess, I expected it to be L4D2 but...that was probably the most disappointing game of the gen for me, the AI is even worse than in the first game and so is the online community, the online community is just horrible

Halo Wars

but it's not on the list, so Left 4 Dead 2

Forza 3 !