^ you should meet my ex

Maybe I'm just reading the title differently that everyone else, but when I think should that means there is at least some probability/chance of it occurring.  Many people have said Gears 2, but if I recall correctly the deal with Epic was for at least 2 games then they'll renegotiate, thus zero chance. 

In my opinion the game with the highest chance is still Mass Effect due to the acquisition by EA and lack of public information as to the specifics of the deal with Microsoft. 

Of course people may be interpreting the question as asking what game(s) they want to go multiplatform.  If that was the intent of the OP then I have to answer MGS4 since I enjoy the stealth genre and want to see what all the fuss is about, but don't want to shell out for a PS3.

RE5. No reason that shouldnt be put on Wii.

But since its already multiplaform with PS3 and 360 then I say X Blades.

Well a few months ago: FFXIII
now: RFoM2.... Killzone 2 (if it's good) and FFXIII Versus.

But I'm also happy without them. No game that I MUST own on other platforms. I will be busy enough with Microsoft's line-up.

RE5 should go to the Wii if possible. Even though I have a 360, I'd rather buy it for the Wii. I'm not even sure I'll buy it for the 360, unless it's a really good game.

The reason for all that is the control scheme, of course.

Mass Effect.

We'd have to deal with a flood of "Suck it, Xbots" comments, but it'd be worth it. Anything to spread the gospel of Tali.

Star Ocean 4

No More Heroes

as i have a ps3, 360 and i am planning to buy a wii. i would say none, cause exclusives often seems more polished.