Favorites and who I think is "officially" the best ever is different for me. My personal favs:

Orson Welles
Jean Renoir
Max Ophuls (can't believe you guys forgot him!)
Kenji Mizoguchi
Robert Bresson
Frederico Fellini
Jean-Luc Godard
Akira Kurosawa
Francois Truffaut
Alfred Hitchcock
Howard Hawks