Depends! I like Taokaka's English voice because of her funny sayings. Guile and Cammy in English makes much more sense to me than their Japanese engrish counterparts. Ryu however sounds much more natural in his Japanese voice than English. So it depends on the character.

I also do Ken's voice in American because i met and spent an afternoon with the VA in an AnimeCon...i know its not the best they could have done for Ken but I love that guy X3