Just watched "Stagecoach" (1939) on YouTube and it's worth seeing not just because it's a classic film, but because of how, 73 years later, businessmen are still making the same damned arguments about government. Check it out at about the 33:30 mark, when the banker (who's looted his bank) is complaining about regulation and the national debt. Sounds like Mitt Romney WAY too much.
That said, it's an elegant film that established just about every convention in westerns and, to be honest, sci-fi films that there is. Watch it and tell me you don't see where Lucas got some story ideas for "Star Wars."