This list is not complete, just the ones I'm interested in.

Too Human                     Aug. 19
Mercenaries II                 Aug. 31
Star Wars Force Unleashed    Sep. 16
Far Cry II                         Oct. 1
Project Origin                 Oct. 1
Fallout III                         Oct. 7
Midnight Club LA              Oct. 7
Aliens                               Oct. 7
Saint's Row II                  Oct. 14
Dead Space                     Oct. 21
Fable II                            Oct. 21
Gears of War II                 Nov. 7
Call of Duty 5                    Nov. 11
Mirror's Edge                    Nov. 11
Age of Conan                   Jan. 1
Just Cause II                     Jan. 1
Red Faction                     Jan. 20
Border Lands                   Feb. 3
Resident Evil 5                 March 13
Prototype                        April 1

        No Dates Yet
Halo: Forerunner (rumored)
Bioshock II
Rainbow Six
Prey II    
Castle Wolfenstein                   
Deus Ex III                 
Riddick 
Black II
Huxley  
Duke Nukem (?)                        
Rage              
Ghost Busters (possibly cancelled)                       
Dark Void                                             
Singularity 

Age of Conan... Jan 1..... Interesting...

I think that one is just a ball park figure bacause Jan. 1 is a thursday, I've never seen an Xbox game come out on a thursday.