Black & White 2 should see some rather nice sales. If it does as well as Black & White in Japan (which is likely) and releases around the same time (September), it'll do 5 million just there alone. In the first 10 weeks - outside of the holiday season - Black & White did 5.2 million in Americas and Europe.
In other words, we're looking at 10-12 million for Black & White 2 provided it doesn't launch too late, and that it launches in Europe. Single-platform, no game is going to beat that, I doubt even Call of Duty will. Although the X360 version obviously has a chance to.
Multi-platform, I'm no expert, as I simply don't know enough about release schedules.
Fifa 13 was mentioned earlier, and it's definitely up there. The '12 version did nearly 9 million in 2011.
If there's a Just Dance game ths year, that'll have a chance to. Just Dance 3 also did nearly 9 million in 2011.
Assassin's Creed is likely to be completely chanceless. The best selling entry to the series - Assassin's Creed II - sold under 6 million in its first year. Jumping up to over 10 million is very unlikely.
Of released games, the best selling one is likely to be Mario Kart 3DS at 6-7.5 million or so.
