The Treasure of the Sierra Madre
Somewhere between a western and a noir, this John Huston-directed parable of greed sets two down-on-their-luck Americans (Tim Holt and Humphrey Bogart) and an old prospector (Walter Huston) off on a backbreaking journey for gold in the mountains of Mexico. Yes, this movie is the source of the (mis)quote "We don't need no stinkin' badges!", but it's also frequently cited as one of the finest American films ever made, and has influenced today's film artists like Vince Gilligan and Paul Thomas Anderson.