Dial M For Murder vs North by Northwest
The Birds vs Rear Window
Naturally, the final four will come down to Vertigo, Psycho, Rear Window, and North by Northwest, at which point things get interesting. I was tempted to give Dial M a strategy vote just so NbNW wouldn't be able to give the other three a significant challenge, as I really don't think it's on the same level as them.
"Puns are the highest form of literature." -Alfred Hitchcock