I think GSP has shown that he is just head and shoulders above anyone else at 170. He's got the winner's mentality, the winner's talent, and the winner's work ethic to go along with it all. A lot of guys have a piece or two of the puzzle, but aren't quite there yet. Until GSP slows down due to injuries or age it's going to be hard to pick someone to beat him outside of the obvious puncher's chance.
That being said, I think when GSP does lose it will be to someone heavy handed. I can't see anyone at 170 with the jiu jitsu or wrestling skillset necessary to deal with GSP on the ground. Someone is going to have to tag him on the feet and put his lights out. There's a lot of guys who can do that. Hell, Matt Serra already did it once.
i completly agree jackelope. GSP will get KOd when he losses his belt again. There are a lot of rising stars that are big strikers in the WW division right now. Swick, Hardy, Johnson. i want to see Swick in there soon, but am lkeing the way the UFC is bringing Anthony Johnson around. Building him up and building a fan base. he has the potential to KO anyone in that div.