Michael Jai White(Guy from Spawn) would be excellent. He's a martial arts expert and he's been training in the martial arts for over twenty years, since he was a little kid. He also is very proficient in boxing, and played in the HBO films movie Mike Tyson, which was mostly about Tyson's glory years and early mistakes.
He played in universal soldier, the return and exit wounds, where he showed a little of his agility and martial arts expertise. He's also quite muscular, with a very impressive and balance physique.
Snipes could do it, but like ervyone said he already done blade so they should get somebody else, though unlike Mericlous said, he did not screw Blade up, he made it better. They should get maybe Samuel Jackson, bcause Denzel is too much of a dramatic actor that a action actor now, USHer, Ice Cube, LL Cool J, and Willl Smith are all okay actors but ush jj and cube would not fit into that type of [persona, and smith would just be too comedic in the role.
Djimon Gaston Hounsou. He's the best and most logical choice at the moment. First, he's actually African which gives him a better idea of how a Wakanda might act. He's also been a damn decent actor in the last few films he's been in. Especially Amistad, Gladiator, Constatine, The Island. etc. After watching the Island, I'm convinced HE'D be T'Challa. Now Reggie has to make it so. I mean why throw out obscure names? ( Ice Cube? No. Jamie Fox? No. Usher?! Wtf!? USHER!?! No. ) Hell, next someone will say " Hey - What about Danny Glover! He's black! He could play T'Challa! "
Here's some more info on Chiwetel Ejiofor:
http://en.wikipedia.org/wiki/Chiwetel_Ejiofor
He also played the villain in Serenity.