Man of the West (Anthony Mann, 1958)

Mann's films (even more so than Fritz Lang's) are the ones I choose for people who think the classical Hollywood cinema was all rainbows and lollipops. Thoroughly unpleasant throughout, it has a feel for verticals in a wide landscape populated by evil psychos. The crane shots are doom-laden and there's a climactic shootout that takes place with the principals on top of one another. A stunner to the last non-formation of the heterosexual couple.