Gears of War
Marvel Vs. Capcom
Mortal Kombat
Portal 2
Portal Kombat 2
L.A Noire
Deus Ex
Uncharted 3
Elder Scrolls: Skyrim
Possibly Mass Effect 3
It's up against some very serious competition, especially from Portal 2, Uncharted 3 and Mass Effect 3 (but I think it's delayed until 2012.) Most of these games are obviously, and I mean obviously from a Zelda-philes perspective, inferior to the Zelda track record. Actually, by almost all standards, every game is inferior to the Zelda standards.
But the trick to winning these sorts of accolades is innovation. This is where I see Portal 2 being strong competition, and L.A Noire slightly less than that. Luckily, Skyward Sword promises to revolutionize the Action/Adventure landscape, and the Zelda formula too. So I hope there aren't any unfortunate bugs or features to hold it back because it's going to have to lift it's game(play). More often than not, the only times Zelda doesn't get Game of the Year is when it's a handheld title, a sidestory off of the back of a recent Zelda (like Majora's Mask), or the judges of these things have an aversion to anything that doesn't have a gun in the foreground.
As a general rule of thumb, Zelda will win from at least 1 respectable publication, as do Mario games. But the smart money may be on Portal 2 at this stage (it was a great, innovative game).