Xbox 360 Games to Buy?

I am looking for a good Xbox 360 game, under $70. I have all the Call of Duty games, Fallout 3, L4D, Halo series, RB 1, 2, and Beatles, Fable II, most Tom Clancy games, Bioshock, Ninja Gaiden II, DMC 4, AC 1 & 2, M Effect 1, Scene It, and hell, you get the picture. I like all types of games, I'm just looking for a fun game that will last a while (50+ hours). I thought Borderlands or M Effect 2, any other ideas?