What is Hitchcock's best movie??

So many to choose from, and they all are superb! I think my favorite is Rebecca, although Dial M for Murder is fantastic!

"Rebecca" from 1940 starring Joan Fontaine is my favourite from Hitchcock though I like some others too,like "Shadow of A Doubt" of "Rear Window" or "The Man Who Knew Too Much".From "The Man Who Knew Too Much" I prefer 1950's version with James Stewart and Doris Day rather than the oringinal version from 1930's.