well, not looking super far in the future, I would go something like this
1) GT5 - 8-10m
2) MGS4 - 4.5m
3) Resistance - 3.6m
4) LBP - 3.5m
5) Motorstorm - 3.5m
6) GT5:P - 3.45m
7) Uncharted 2 3.xxm (could move up the list if it has legs or gets bundled like Uncharted was)
8) Uncharted - 3m
9) God Of War 3 - 2-3m (could go as high as the #3 spot, but I'm not holding my breath)
10) Killzone 2 - 2.2m
Obviously there are other big exclusives that could jump up the list, but given the information we know now, this is what it will probably look like over the next year. As a final note, I put some games the same as their current total, but that is because they are so old now, they sell very small amounts outside of holidays. Obviously they will creep up, but generally at the same pace