They're also called maestros (to disambiguate for those technically inclined). Great ones are heard instead of being seen. By the time we see them on stages, most of the things great conductors do have already been done, and they're basically metronomes. The even better ones have a showmanship in them to help the audience to appreciate the music even more. Check out (rehearsal) performances by Szell, Solti, von Karajan, and our very own Michael Tilson Thomas.
