The Treasure of the Sierra Madre (John Huston, 1948) 
What is so refreshing about this film even after so many years have past is that , for a film considered the equivalent of a blockbuster for its time, it is so dark and dour. Of course time has made famous two elements of the film that really aren't its most important aspects: the "We don't need no stinkin' badges" line (which is incorrectly quoted) and Walter Houston's much parodied dance. These are celebrated more than the film, which in itself, isn't really something to be. For a major studio picture of the era, it's certainly an anomaly, with actual location shooting and a completely unlikable protagonist. It's a film that could only be made because of who was associated with it. John Huston wrote and directed and doesn't spare the bleak nature of the novel. His direction is exceptional, capturing the harsh, desolate landscape as easily as the harsh emotional nature of the film. The adventure/treasure aspect of the story only sets up the real crux of the film: what materialism and greed do to the true nature of man. Bogart's Fred Dobbs is the ultimate example of the poisoning of greed. As the film progresses, Dobbs becomes more and more paranoid and irrational until he meets his untimely end. He is a completely unlikable character, full of flaws and awful character traits. It plays so completely off of the archetypes of films of that era that it's no wonder the film was a commercial disappointment. It's an overwhelmingly impressive performance by Bogart and proves he an actor beyond being the tough guy type. What is also impressive is that the good guys don't save the day; the film ends on failure on one level. It's this failure of material fortune that finally makes the characters reveal that their happiness exists outside of the treasure. It's a mixed ending, but Huston sells it by his near flawless direction.