In the MMA world one of the most interesting match ups would be Chael Sonnen and "the axe murderer" Wanderlei Silva. Last week Chael was fighting on the 1st card ever on the new channel Fox Sports 1. He defeated Shogun Rua (who is a close friend of Wanderlei) by 1st round guillotine choke. After the fight Chael went out of his way to call out Wanderlei.
A couple days later Dana White (UFC President) told Ariel Helwani of mmafighting.com that Wanderlei doesn't want to fight unless he gets more money. That ultimately become moot because Wanderlei's just sent out a video if his epic rant against Chael Sonnen
Why I say this will never live up to the hype is because of their styles of fighting. I believe that Wanderlei will hold up his end of the bargain because of his aggressive stand up and willingness to go for the kill, but its Chael who decides how this fight will turn out. Chael is a wrestler who takes his opponents down and makes them stay down. Chael has never been one to go toe to toe with an opponent. So a boring match up with Chael taking down Wanderlei will never live up to the hype.