Games Off the top of my head that I'd assume Microsoft paid for exclusivity, rather than paid for development up front. We'll never know the actual figures of what happened, so debate all you want. Not many of them we're pre-existing franchises.
Ace Combat 6
Dead Rising
lost planet (timed)
Bioshock (timed)
Eternal Sonata (timed)
Tales of Vesp (timed)
Ninja Gaiden II (timed)
Star ocean IV (timed)
The Last Remnant
Gears of War
Gears of War 2
Mass Effect 2
Splinter Cell double agent
Magna Carta 2
GTA DLC
Fallout DLC (timed)
Tomb Raider DLC
MW/MW2 map packs Timed
I can imagine at this point in the game ME2 and Gears3 would be cost-prohibitive to buy. I really don't know if microsoft can continue buying exclusive content, so no If this gen continues another 5 years ms won't have much.
This is not to say that Sony may have paid for some games like Valk chronicles, mgs4, haze, but i believe Sony's strategy is more about paying up front.
