As others have said if were talking multi-platform then i would have to say COD4.5 would be a contender as would Guitar Hero World Tour just because of the amount of platforms it is on.
BUT if were talking exclusives and console specific then i think it is pretty obvious Gears 2 will win hands down. The thing has not even started to get the publicity it will and is everywhere already. Even if the game is a flop review wise i can still see it doing mad sales. Not Halo 3 mad but deffinatly around the 4m mark by the end of the year. On the PS3 i just cannot see anything exclusive getting near those numbers. If LBP was a Wii game then i bet that would but because it is a PS3 game i can't see it selling more then say 2m max by the end of the year. People have to remember Gears 1 won game of the year for 2006 and 2007. I would not be surprised to see it win 2008 as well. It is not some average run of the mill game, it is a jugernaut of a title that will shift units like no tommorow. Sony has nothing coming that can do that right now.
