Before this is moved though, I've got several coming up.
1.Prototype - Looks fun and I reckon I'm going to like the massive scale of the fights. Coming out soon
2.Aliens:Colonial Marines - Actually been changed now to Aliens Vs Predator, maybe with Marines thrown in, but still seems awesome. Coming out late this year/early next year I think.
3.Modern Warfare 2 - No explanation needed, my social life is going to be destroyed... Coming out late this year.
4.Bioshock 2 - ...
Also, try some games already out. Gears of War 2 is good fun once you get good at it, and Call of Duty: Modern Warfare is just a Xbox 360 legend. Some less mainstream games that I like are Bioshock ( love the plasmids and the Big Daddy/Little Sister partnership) and, surprisingly, Turok. I played the original on the PS2, and I leapt at the 360 version. Online isn't that popular as not many people have heard of/play it, but the single player is fun and challenging on the harder difficulties.
Although, it would be easier if I knew what kind of games you liked.