1) GSP - He beat two modern day MMA legends, who are routinely mentioned among the best P4P in the world.
2) Cro-Cop - OWGP Champ 4 Fights, 4 First round KO's.
3) Liddell - KO wins over 3 very talented and game fighters (Randy, Babalu, Tito.)
4) Hermes Franca - Would be #1 if he fought some better competition. Still, he stopped all 7 of his opponents in 2006.
5) Anderson Silva - KO'd Franlin and Leben in less than 4 minutes combined. Also KO'ed Tony Fryklund in the first round. Lost once by DQ (Kicking a downed opponent)
I know these are all UFC fighters. I didn't mean for it to be that way but these are my picks and I'll stick with them. What are yours?