I have to confess that Norm's initial listing is pretty appealing:
My top four Hitchcock movies in rank order: (1) Psycho (2) Vertigo (3) North By Northwest (4) The Birds.
Bubbling unders: Marnie; Shadow of a Doubt; Strangers on a Train.
For me though, I'm not quite convinced that I would rate Psycho in the top listing (it's powerful but it's not a favourite) and nor am I quite in line with the fandom for Marnie (which garnered a lot of positive feedback on the FB comments).
My list would probably be as follows:
1) North by Northwest - still adorable, totally enjoyable and with Cary Grant and Eve Marie-Saint. Brilliant
2) Vertigo - disturbing, but delightfully intriguing - and with Jimmy Stewart and Kim Novak (even if she did get her knickers in a twist about music)
3) The Birds - far, FAR freakier than Psycho, totally disturbed me. The colours when you see the farmer's eyes... *shudder*
4) Shadow of a Doubt - for Joseph Cotten
5) The 39 Steps - because it's just such a great romp