goboy: Big tip o’ the hat for Amarcord. Call me crazy, but it’s my fave Fellini, over more conventional choices like 8 1/2 and La Dolce Vita. La Strada and Nights of Cabiria are pretty good, too.
Last year’s Titus was pretty cool; good call, JoeyHemlock.
Others:
Proof. Not sure if this is really an “art” movie, as it’s pretty straightforward story-wise and doesn’t have wacky acting or photography. But it’s small, quiet, and very thought-provoking (and occasionally hilarious), so it’s probably more “art” than ordinary. (It’s also from Australia, so it’s “furrn.”)
The films of Hal Hartley. Some of them are fairly accessible; others are pretty strange. The one I usually recommend to people to start with because it’s a good compromise between the two sides is Flirt. I’m not going to say too much about it; just watch it.
True “art house” moviemakers: the Brothers Quay. I’ve mentioned them before in other threads; here they are again. Don’t ask anything about their work; just go to a big video store and ask for their movies by their name.
Another true “art house” filmmaker: Jan Svankmajer. Again, just go by name. Start with Conspirators of Pleasure.
An art filmmaker from a while back: Jacques Demy. His Umbrellas of Cherbourg is probably his best known work (although Donkey Skin was more famous ten years ago, prior to the Umbrellas restoration). It’s impossible to describe, except that it’s a full-length musical in French, it’s tons of fun, and the end is very moving.
And one last observation on “art films” – Isn’t it funny that almost any movie more than forty years old or so that still has a reputation and gets watched on a semi-regular basis is called an “art” movie? Take Fritz Lang’s M or Metropolis, for example, or Dreyer’s Passion of Joan of Arc, not to mention most of Kurosawa’s earlier work (Ikiru is a flat-out masterpiece). And of course, there’s the granddaddy of them all, Citizen Kane. They weren’t necessarily art movies in their day, but we’ve gained sufficient distance from them that it’s almost like watching a movie from another country. (Hey, what? Most of those movies are from other countries? Well, gawrsh. You know what I meant.)