I'd say Mass effect. In fact I got a 360 and the game, but I don't play it anymore (don't like the controller, the noise and blabla). I'd love a release on the ps3 even if the game is not perfect.

Most of the Xbox exclusives that i liked ended up on the PC (Mass Effect and Bioshock). However there is one i want and that is Star Ocean. But ill probably just buy and Xbox for that oh and ToV... hope they make a bundle.

XBLA offerings... Rez HD, Extend Every Extra, Castle Crashers (but with fixed netcode), and Braid.

More than one, i know :)

I own an Xbox 360, but if I didn't, it would be Star Ocean 4.

ffxiii

that's multi platform....?

make it exclusive :P Easily on one of the biggest 360 games this year.

like halo i guess, its better than gears

I can't think of any 360 games I'd want, aside from GoW which I don't think belongs on the ps3.
The only other games I really really want to play is an upcoming Killer Instinct, but it will probably be another rare dud. Although here is to hoping for a reinvigoration of the franchise.

Tales of Vesperia.

I'll still buy a PS3 copy, should one come out, if they put original voices on it.