There are lots of possible candidates for it, but communism ruined it all in China.
Anyway, left are:
1) Africa (don't underestimate it, it could grow much faster than any other country, iff it only could free itself from all those nasty colonialism consequences...)
2) Europe, united with all of its parts (and I mean especially the eastern ones)
3) Middle East + India; may seem strange (to some of you), but there you can find the top of the top of human-brewn Culture -- no other region on earth can beat this.
America, you have to "die" (read: take the last place on earth for some decade), because it was you trashing whole world in this financial disaster. This is not popular, so you people will not agree -- the same as children never agree when it comes to take some bitter medicine...