Dances With Wolves
Dubbed "Kevin's Gate" (after Cimino's earlier western flop Heaven's Gate) before it came out, this epic western shut the wiseacres up about a minute after it premiered, making a modest $420M on a $22M production cost, and garnered producer/director/star Costner two Oscars personally, and seven for the film. One of the few films that ever felt too short at the 3-hour mark, the director's cut added nearly another hour. It was the first western in almost 60 years to win a Best Picture Oscar, and stands as a monument to both the western film genre, and what can be done when someone who knows what they're doing doesn't listen to everything Hollywood thinks is wisdom.
Best Picture, Best Director, Best Adapted Screenplay, Best Cinematography, Best Film Editing, Best Sound, Best Original Score