These are my guesses of which games will be the Game Of The Year on the system specified.
PC-Sins of a Solar Empire; so far, it's the highest rated game that came out this year on the PC, si it does have a high chance of winning.
Wii- Super Smash Bros Brawl- One of the best games on the Wii to begin with, and most people agree. It's either this or Super Mario Galaxy, but this on got way higher rating, let alone fan service.
PSP-Crisis Core: Final Fnatasy 7- Come on, it's Final Fantasy-one of the best on-running series besides Mario. It may not be the best FF game, but it sure is the best PSP game out there so far.
PS3-Uncharted: Drakes Fortune- Sigh, if a game comes out for the PS3, it usually comes out on the XBox 360, like Devil May Cry 4. So this, same with the XBox 360, were the hardest to come up with. Out of games only on the PS3, this one is the best.
XBox 360- Lost Odyssey- It may not be as good as Final Fantasy or the other Square Enix games, but Lost Odyssey gives fans what they want- lots of leveling up and an epic storyline like most Square Enix games. Plus it's thebest that is only on the 360 to come out so far this year.
DS- The World Ends With You- Going to win hands down unless an even better game comes out, but so far it doesn't look like that will be happening. It's either this or The Legend of Zelda: Phantom Hourglass.
Multi- Grand Theft Auto lV-Going to win, and everyone knows it. Unless Star Wars: the Force Unleashed can beat it, but I don't think that's going to happen.