Well the main factor is if Zelda Wii makes it this year. I'm skeptical about it, but if it makes it, then well we know the nature of Zelda console games and high praise haha. I won't name what I think the GOTY will be because that would be silly with none of these games out but if I had to guess potential nominees I'd think:
Super Mario Galaxy 2
Zelda Wii
Bioshock 2
Mass Effect 2
Halo: Reach
Starcraft 2
Last Guardian
God of War 3
Gran Turismo 5
Metroid: Other M
Excuse me if I'm missing any, but there is a lot of big brands in 2010. I'd give outside shots to Monster Hunter 3, Heavy Rain, Splinter Cell: Conviction, Epic Mickey, Fable 3, Final Fantasy XIII, etc. All I know is 2010 is cluttered with some of the biggest projects ever. There has never been a year with this many big games, and the closest rivals are 2004 and namely 2007. Going to be fun to be a gamer this year.