well, according to the people intelligencia decided to kidnap, the list goes as this - with no particular order;
victor von doom (doctor doom)
henry pym (who the hell knows what he's calling himself these days?)
reed richards (mr. fantastic)
henry mccoy (beast)
t'challa (black panther)
bruce banner (hulk - green, gray, whatever...)
tony stark (iron man)
samuel sterns (leader)
banner says that amadeus cho is the 10th. and he also somehow calculates dr. doom's smarty-score instantly when he was hit by leader's dumb-ray - 4.956.342.261, but of course he may be bluffing.
i agree that t'challa doesn't seem to fit in there - he is an awesome guy of course, but not exactly on par with the others. also this list needs more supervillains, or at least some anti-heroes and maybe neutrals. doc ock maybe... then mr. sinister, apocalypse and mandarin can fight to the death for beast's place... that would be awesome, oh wait... two of them are already dead, so let's welcome mandarin to the big leagues.