While I will always personally favour "Un Chant D'amour", this movie is without a doubt the single greatest full-length film I've ever seen. Even without its unsurpassed historical significance it is utterly terrifying and absolutely incredible in every known way possible, with such likable characters and unforgettable performances from Margaret Lockwood and the charming Michael Redgrave. Hitchcock is not a good director. He is not a great director. He is the best damn director who ever lived.
The only film so breathtaking that it has made me disregard all of my opinions on any other movie after watching it, because there is simply nothing else like it and there never will be again. This is not appreciation of "Un chant d'amour" I am speaking of, this is pure unadulterated love. The best film ever made? Yes, but even that would be understating things.