Forrest Griffin is probably the biggest win in Tito Ortiz's career, and even then a lot of people dispute that decision. People say "Well he's only lost to great fighters" but they also fail to look at the reverse point---that he's never beaten any great fighters either.
Wanderlei Silva, and Vitor Belfort. Honestly why does everybody still whine about the Tito/Forrest fight? Even Forrest has said he lost that fight and Tito also had a bum knee that he probably shouldn't have been fighting on.