I have always played F#, so to me it sounds more correct. However, my theory is telling me it should probably be a G# because the left hand chord is B#, D#, implied G#, and A natural (just a 9-8 suspension). This would make the chord a V9 of the current tonicization of c#-. Can someone back me up on this?
I also play the A# - I have equal numbers of recordings of both ways.