You want literature, but some of the later Clint Eastwood westerns were great (really all of the spaghetti trilogy - the first based on Yojimbo - ending in Good Bad and Ugly, and High Plains Drifter -> Pale Rider).
Also The Magnificent Seven (as above a reworking of The Seven Samurai - actually I saw a quirky sci fi version with Robert Vaughn too), The Wild Bunch, and probably type in 'best Westerns of all time' - though a lot of them aren't