Some important names I wanted to touch on since they've been mentioned;
Hughes; Good answer. Long dominant career, only lost to one of the GOAT's near the end of his run. Definitely up there, but I feel bones has trumped his run at this point. I'd put him above hendo or right at par with him, as I really feel Hendo has gotten by on "luck" more than any other one thing throughout his career. Not to say Hendo's career isn't amazing, every fighter gets lucky and it's a huge part of every fight. But he seems to have squeaked by on more occasions than most.
Randy is a good mention, one of 2 men to hold titles in 2 divisions, never really incredibly dominant however, I never felt he was invincible the way GSP, Silva, Fedor and Bones felt invincible.
BJ Penn I considered, but similar to Tito/Chuck he's just run his name through the mud with his half-hearted run at WW after his UFC return.