Lot of good games did come out this year so we'll see what they choose. Also we'll see how prevalent the bias is towards when a game releases. Lot of good games came out this year before the second half, such as God of War 3, Red Dead: Redemption, Super Mario Galaxy 2, and Mass Effect 2, to name a few of them.
Personally for me, throughout the year Red Dead: Redemption and Super Mario Galaxy 2 have easily been my top 2. If I were deciding I would probably take RDR over SMG2 but really it is a thin line. Followed by AC: Brotherhood and Halo: Reach. Been a good year though.