This is kind of an open ended question. Be more specific please i.e..... Who would you never want to fight in the ring? or in a street fight?
I wouldn't back down from any fight in the ring. Now with that said...First, hopefully Big John would be ref'ing the match and would provide a proper stoppage for when I got knocked out. Second I know there would be a doctor on site so at least I would have the mind set that I wasn't going to die. I'm going with the rest of the crowd and say Fedor, CC, Hendo, Chuck, AA, Hunt and there are many more.
I would least like to fight Bas or Tank in a street fight. Bas, enough said, is a mean SoB and Tank just because he seems like the kind of guy that gets pleasure in beating people up and doesn't know when to say when.
AbbaZabba, you my only friend!