the only multiplatform games i played were on PC, i cant speak for console multiplats

1. call of duty 4
2. orange box/portal
3. bioshock
4. fallout 3
5. dead space

honorable mention to burnout paradise

Call of Duty 4
Burnout Paradise
GTA 4
Resident Evil 5
Bioshock

1. Bioshock
2. Dead Space
3. Oblivian
4. Call of Duty 4
5. Fallout 3

The following list is only from games I have played.

1. Burnout Paradise
2. Super Street Fighter II Turbo: HD Remix
3. Mega Man 9
4. Shaun White Snowboarding
5. Assassin's Creed

as a note, I've only owned 7 multiplatform games this generation, and played a few more (maybe 1-2) with over half being a Wii multiplatform with significant control changes which make them feel like platform exclusives to me.

1. Call of Duty: Modern Warfare
2. Burnout: Paradise
3. The Simpsons Game
4. Prince of Persia
5. Gears of War

Three guesses which one I threw in there to piss people off.

1. Elder Scrolls IV: Oblivion
2. Grand Theft Auto IV
3. Assassins Creed
4. Call of Duty 4

and those are all I care for, though CoD4 was pretty shitty.

Gears of War

Wow, I made that one a little too easy.

1- Oblivion
2- Bioshock
3- Call of Duty 4
4- The Orange Box
5- Rock Band/Street Fighter 4.

1. Fallout 3
2. Fallout 3
3. Fallout 3
4. Fallout 3
5. Fallout 3

The game is so amazing for me it deserves all 5 slots.