Hmm, Possible? Probable? Im not sure, I think people have started to wise up that COD WAW =/= Call of Duty Modern Warfare. So for Halo to be #1 shooter combining platforms two things must happen.
1. Something has to fracture the Call of Duty userbase, Battlefield, Medal of Honour etc and even Halo itself to break the overwhelming wad of multiplayer gamers who play that game and buy it all at the same time. The fact that its Treyarch certainly helps.
2. Halo: Reach has to be that good. (I trust it will be haha).
Do you know what its like to live on the far side of Uranus?