Blue Velvet and Vertigo are great. I haven't seen the others on cavorting's list (well, I did see The Wild Bunch a long time ago, but don't remember it). Wings of Desire is on Hulu, so I'll watch that soon.
Everything on nec13's list I like (except Night Moves, which I haven't seen). The Third Man especially is great stuff.
Haven't seen anything on mostlymeat's list, though I've been meaning to check out The Devils for a while now. I'll probably watch that soon and check out the rest at some point in the future
HM from me are The Good, The Bad, and the Ugly; Picnic at Hanging Rock; Kozintsev's King Lear; Polanski's Macbeth; and This Is Spinal Tap.