The Treasure of The Sierra Madre (1948)

Directed by John Huston

John Huston won a Best Director Oscar for this film.  And he absolutely deserved it because it's a superbly directed film.  My opinion differs somewhat on the story, but others love it.  Over the course of the movie the characters go from rags to riches, or so it seems.  There is trouble brewing ahead.  You can see how this influenced the genre of the heist film.  Stanley Kubrick's The Killing being one example.