This is the only Hitchcock movie to win best picture. One of the things that makes this movie great is Lawrence Olivier's performance as Max DeWinter. Supposedly, he despised Joan Fontaine in real life and used this in his performance... seems to have worked. The best part of the film is when the camera works its way around an empty room as Olivier describes a scene. Check it out.
4. Rear Window
Not much to add to that, since I'm sure you've seen it. As far as Hitchcock movies starring Jimmy Stewart, I think this movie runs circles around Vertigo.
This used to be higher on my list but has slipped a little. Hitchcock has Grant and Bergman in the same film here, which I think gives one of his best results ever. Rumor has it that Hitchcock was investigated after this movie came out because it has some discussion of an atomic bomb, before the bomb was actually completed. What to watch for: a great crane shot that comes all the way over a party, down to a key in Bergman's hand.
2. Shadow of a Doubt
As a friend of mine once said, this is Hitchcock's most subversive film. I agree with that. Joseph Cotten plays Uncle Charlie spectacularly, and the rest of the cast does well too. Hume Cronyn's bit part in this movie is one of my favorite characters in all of Hitchcock. If the first five minutes of this movie don't lock your interest, I'll give you a rebate.
1. North by Northwest
Textbook. Besides Psycho, of course this is Hitchcock's most referenced movie. This might be Hitch's longest movie, but the script is interesting enough to keep the audience going. Cary Grant delivers some extreme hilarity as well. The scenes to watch are the restaurant at the beginning, the crop duster (of course), the auction house and Mt. Rushmore (of course). My favorite part of the crop duster attack is when he's waiting around on the side of the road. You think one of those cars is going to do a drive-by with machine gun and just take him out.... but it's a crazy crop duster that comes and gets him! Genius. I wish I had seen this movie in the theater originally, without knowing the crop duster was coming.