Like a lot of these lists, all the picks below in no particular order and are subject to daily change. Except the first one.
Black Belt Jones - obviously this is a pretty lousy film by pretty much any aesthetic criteria you care to apply, and yet it somehow manages to be one of the most consistently entertaining movies I've ever seen. Also, Gloria Hendry.
8 1/2 - I grew up with a film archivist, so I saw this projected on a bedsheet in 35mm when I was 12 or so, and it changed everything. Pure cinema.
The Miracle of Morgan's Creek - the funniest thing I've ever seen. Is Eddie Bracken an unrecognized genius? Discuss...
To Live and Die in L.A. - Petersen and Dafoe face off with Friedkin pulling the complex strings. Add a kick-ass score, beautiful cinematography and another brilliant car chase from the man who gave us The French Connection.
Touch of Evil - Orson in a fat suit, Mercedes McCambridge as a lesbian junkie biker, Marlene Deitrich as a broken down old madam and Charlton Heston as a Mexican cop. There's a lot more on offer here, but if that first sentence doesn't get your attention I'd like to direct your attention to the Adam Sandler thread...
Conan the Barbarian - how could any movie about chopping off peoples' heads, stealing jewels from giant snakes and sleeping with lots of whores not gonna have a lot going for it? Add the fact that it was written by John Milius and Oliver Stone and we have a one-of-a-kind classic.
Pat Garret and Billy the Kid - the restored version is the only way to go. This is a big, lumbering mess of camp-cooked western goodness, and distills Peckinpah's concerns down to a few well-chosen shots. There's a beautiful score by Bob Dylan, great leading performances from Coburn and Kristofferson and the best (and first) use of "Knockin' on Heaven's Door" in all of film.
Singin' in the Rain - one of the first movies I ever saw, the sheer joy and wonder of Gene Kelly persists to this day. And I stillv have yet to see legs to match those of Cyd Charisse.
The Haunting - a ghost story where the ghost remains off-screen, this is still the scariest movie I've ever seen. Dogs bark, statues move and doors bulge, and beneath it all pulses the wild river of frustrated female sexuality.
Vanishing Point - a chase movie written by Albert Camus. Examining the wreckage of the hippie era and the inevitable spiritual damage of the death of the revolution, there is nothing like this true oddity. Cleavon Little owns as Super Soul, and the sudden ending is a slap in the face.