With the new advertising campaign for Halo ODST kickin' in, there will be more Halo 3 copies sold. I mean, Halo is THE game to get for the Xbox360, just like Mario Kart for the Wii.
MS could also release a special edition for the whole Halo trilogy and ODST. Halo + Halo 2 + Halo 3 + Halo ODST for $90 or whatever.
GT5 could match Halo3 just as a bundle with every PS3slim sold.
Imagine not having GamePass on your console...