King Mo
The Soul Assassin (Tanner took his soul)
Fedor in the US
Wandy in the US
Cro Cop in the US
Marcelo Garcia. 1 and done
Gabe Gonzaga
Kang comes to mind but I don't if its hype or potential that wasn't lived up to.
armbarseverywhere -Really? I'm Aussie so root for him, but as soon as he went up in competition he lost 3 in a row. But that's just my opinion.bigbenpie - How has no one mentioned G-Sot??
Because G-Sot is fucking legit.
Tim Sylvia 
Vera and Sokodjou (however the fuck you spell that) are the biggest IMO.
Both were uncrowned kings for a short period of time. After Sok KO'd Nog and Arona people were going nuts about him, Vera was considered the uncrowned UFC champ for awhile and people were talking about him holding 2 belts at once after he beat Mir. He's gone 4-6-1 since.
Huerta is close, but to be fair he pretty much stopped taking MMA serious and I think he was modeling/acting and banging chicks, good for him.
Gorilla_keylock -Tim Sylvia
Wasn't he the longest reigning UFC champion and first man to beat the World's Strongest Man purple?
The argument could be made that Tim did more with less than any MMA fighter ever. He's the ultimate overachiever.
How about Rickson?
Looked great against cans and not so great against a pro wrestler. Avoided Saku like a used needle.
Rickson-Saku or Rickson-Frank Shamrock would have been all time fights.
Wonderboy, Uriah hall..... Kimbo....
fraz1001 - How about Shane Carwin
He would have beaten Cain unconscious when that fight was signed. He missed his window due to injury and age and lactic acidosis.
Shane will always be the man who broke Brock's chin
Dave Terrell.. It was like, if Jon Jones got annihilated by Shogun.
BernardHopkins -bispingpokedmybrowneye -Machida
Shogun
Arona
Rampage
Crocop
Nogueira Brothers
Gomi
this list is actually pretty accurate if the only thing you ever watched was their UFC careers
eh not really. Arona never was in the UFC. Rampage, Minotauro, and Shogun have been UFC champions (ok so Mino was a interim champ but still, it counts somewhat). Agree on Crocop and Gomi though in regards to UFC careers.