Vertigo

A Hitchcock classic that gave the film world the famous dolly zoom, where you move camera whilst zooming in to give a literal vertiginous effect. The plot has some holes (to say the least) - no spoilers if you haven't seen it, but by the time that the twist is revealed about two thirds of the way through you'll be saying - hang on, this makes no sense whatsoever. It's more about the atmosphere though, with great use of technicolor and one of the greatest cold open sequences in movie history with Jimmy Stewart dangling from a gutter and about to plummet from a roof top.