From Robin Williams playing a psycho in One Hour Photo to Jim Carrey playing, well... a psycho in The Cable Guy, actors have always enjoyed upending expectations with their roles. Home Alone's Macaulay Culkin? Check (The Good Son). E.T. cutie-pie Drew Barrymore? Check (Poison Ivy). But those role reversals are particularly jarring in Westerns, where the line between good and bad is so firmly etched in the sand. Which good cowboys have most memorably gone bad?

Burt Lancaster in Vera Cruz (1954)
There are no out-and-out heroes in this darkly humorous tale of greed, and Burt Lancaster's unscrupulous mercenary doesn't come close. He's a wolfish lout who's a delight to watch on screen and a far cry from his Oscar-nominated role as Sgt. Milton Warden in From Here to Eternity. Making him seem more despicable still is that he plays opposite Gary Cooper, who is clearly the lesser of two evils. Critics were stunned -- not necessarily for the better -- and chances are, you will be too.

Henry Fonda in Fort Apache (1948)
When not filming movies, Henry Fonda was often flying kites with best friend Jimmy Stewart. (Seriously.) But that doesn't mean he hasn't played the villain: While his role as the evil man in Once Upon a Time in the West is flashier, his turn here as a lieutenant who leads his men to be slaughtered on the cross of his own ego deserves accolades -- it's delicious to see Fonda playing the arrogant fop.

James Stewart in Two Rode Together (1946)
This movie deserves special mention because it represents a fascinating case of reverse casting for leads Stewart and Richard Widmark. Whereas audiences are used to seeing Widmark giggle while throwing grannies down stairs in Kiss of Death, here he plays the scrupulously good cop. Meanwhile, Stewart (whose penchant for playing good-guy everymen would color audience opinions of him for the rest of his life) is the craven, scheming sheriff who partners up with him, for better or for worse.

John Wayne in Red River (1948)
In this great clash of the generations (not to mention acting styles), Duke plays the adoptive father to Montgomery Clift's cowpoke. Being abrasive and stubborn are qualities that have made the Duke the quintessential cowboy, so it's fascinating when those very same attributes are called into question, in this dark role as an Ahab-esque villain. When Wayne leads the cattle drive into deadly territory, Clift trumps his authority. And so Wayne plots to kill Clift, his son. Over cows.

Lee Marvin in The Man Who Shot Liberty Valance (1962)
Lee Marvin is probably best known to audiences for his heroic portrayals in war movies like The Dirty Dozen. But one of his most magnetic performances is as the manic gunfighter Liberty Valance in this John Ford Western. Full of violent energy, Marvin's character prefigures Alex's in A Clockwork Orange -- a portrayal of complete freedom that spells doom for civil society. In case you missed the symbolism of his name, there you go.

Robert Duvall in True Grit (1969)
It's a relatively small performance, but long before Duvall was cemented as a timeless hero thanks to his performance in Lonesome Dove, he was the villainous outlaw Ned Pepper in this John Wayne classic. But with the clarity of hindsight, it's rather fun to watch Duvall trade shots with The Duke, knowing that he'd play an old codger like Rooster J. Cogburn before long. Not only that -- during a climactic shoot-out, Duvall comes at an unarmed John Wayne and nearly sends the Hollywood legend into the great hereafter.

Yul Brynner in Westworld  (1973)
Surely capitalizing on his heroic turn in The Magnificent Seven, this movie from Jurassic Park author Michael Crichton envisions Brynner as a short circuited robot cowboy who hunts down a couple tourists in a futuristic Wild West amusement park. Brynner is appropriately forbidding, with a steely gaze and lack of emotion that makes him more evil than the gesticulating, scenery chewing menace of, say, Jack Palance in Shane. He's a black-hatted gunfighter for an age that saw another cyborg duded up in black (Darth Vader) as its biggest villain.

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