It's way too early to call GOTY. Hell, November is too early to call it. 2003, I said Wind Waker was my GOTY in October, then Prince of Persia Sands of Time came and really made it competitive (still really don't know which I liked better).
That said, I think the Legend of Zelda should make it pretty interesting at the end of the year. RE4, God of War are also making it interesting. Chaos Theory should be a candidate, but because it is so much like the previous two installments (is Co-op and a knife enough to distinguish it?), I think most people will be hard pressed to make it GOTY. Maybe the Multiplatform GOTY, but I'd be very surprised if it got the nod over all the other great games this year. I'm waiting till December 31st to cast my vote, because you never know when a game will come out of nowhere to steal it.