Just one?
Blues Brothers, Casablanca, One Flew Over the Cuckoo's Nest, Apocalypse Now, Rosemary's Baby, Escape From Alcatraz, Dirty Harry, The Good the Bad and the Ugly, Scarecrow, The Shining, Blue Velvet, Bullitt, Papillon, The Thing, Young Frankenstein, Trainspotting, Life of Brian, The Birds, E.T., Scrooge('51), 2001: a Space Odyssey, 1984, Clockwork Orange, Godfather, Unforgiven, Star Wars(all), Indiana Jones(all), Alien(all), Enter the Dragon, Forrest Gump, Shawshank Redemption, Fried Green Tomatoes, Wild Thing, Good Will Hunting, Usual Suspects, Pulp Fiction...
My favorite is Blues Brothers (have seen that movie more than twenty times )
Cheers,
SB