The only game I've played so far that I believe is worth of the Game of the Year is Mass Effect 2. Yes I've played Red Dead Redemption, Black Ops, Halo: Reach, GoW3 etc... But overall, I find that those games are pretty much rehashes of older games. You can disagree with me, but the core gameplay remains basically unchanged from previous games from the studios.
However, Mass Effect 2 really shakes things up. The gameplay is completely revamped (though I sort of miss the Mako and the elevators), with an engrossing story that can span over 30 hours. Serious customization within the story, and an epic ending that can literally change the entire game was we know it. I've played it over 10 times and I'm still having fun.
As for what I'm looking forward to in 2011, definitely Mass Effect 3 and Dragon Age 2. I pretty much look forward to anything made by Bioware, because they have proven time and time again that they are some of the best in game development. Though there are some other games, ME3 and DA2 are the only definite must buys so far.