This is definitely an epic fight and go either way; and no doubt will make the UFC a lot of money which is why I think Dana wants it more than anyone right now.
All that aside I think 8/10 times GSP would win this fight by decision. Silva is only going to beat GSP with a KO. We all know GSP has no intentions of striking at all with Silva.
I also predict a really
boring fight. GSP is going to sit outside of Silva's range. Silva will be very hesitant to move into range due to the takedown threat. Couple that with Silva preferring to counterstrike and it will make for a lot of dancing around with not much going on in terms of actual hits. A lot of positioning, feints, and footwork will be happening but not much else.
Why GSP then? GSP will eventually get a takedown when Silva gets frustrated because GSP is the more patient fighter. Silva has great BJJ don't get me wrong, but it won't be good enough to submit GSP from guard. I do see Silva having the ability get eventually get back up, but GSP will eventually get him back down again thus scoring more points.
Or... GSP could surprise us and come out very aggressive which obviously will make for a better fight from our point of view