If you were to ask me who makes the scariest movies, I would say it's definitely Alfred Hitchcock. He made movies that were scary not because of the monsters, but because he shows us the evil of our own souls. Most of his movies could actually happen, and that's what makes them all the more frightening (I'm excluding The Birds. There's just no way that could happen). Sorry) So, since Halloween is when we celebrate everything scary, I'm celebrating Alfred Hitchcock. Here's my favorites:
Rear Window
Psycho (note: Only the original had anything to do with Hitchcock)
Vertigo
North By Northwest