Mass Effect 2 (Yes its still confirmed to be released as a trilogy on 360)
Too Human (Also confirmed recently at GDC as trilogy on 360)
Ninja Gaiden II (Not really a franchise, but its a anticipated exclusive)
Left 4 Dead (for 360 and PC)
As you can see Mass Effect 2/3 Too Human 1/2/3, thats 5 games alone.
MGS4 is the last of the franchise
GTA4 is mutliplatform and if history tells us anything the 360 will sell more then the PS3 just like CoD4
FF13 sure to be great, but also 1 title
Now im not denying PS3 will sell alot, but after recent announcements and crap, I withdraw my prediction and I think 360 will keep doing fine.