Any direct English equivalent for "佩服"?
I think "appreciate" should be the right word.

I'd say the first meaning, "to be grateful or thankful for", of the word is not related. But 2nd and 4th meanings are good matches. See http://dictionary.reference.com/browse/appreciate for the meanings that I mentioned.

I am not sure if one can apply it to somebody. Correct me if I were wrong.