That GSP vs. Shields fight was bullshit! Not because GSP won, he definitly won every round 10-9, but because neither fighter did anything to finish the fight @ any time... If not for some other fights on the card, and you know which ones, I would say UFC 129 was a waste of time & money.
On that note, Silva has another fight before the end of the year, it is unlikely that GSP will fight again in 2011. If both fighters remain undefeted then they have agreed to fight at a catch weight of 180 lbs.
I think Silva would win. But none of us has seen GSP that big so it's really anyone's guess... That's why this fight, barring a loss by Silva, WILL happen early 2012.