Top 10 Western villain performances?

I don't have a list but ..............

Fonda is the classic villain performance of all-time to me - a stunning piece of casting against type that is just unforgettable.

I'd say Harris in Unforgiven is close to making this list - not as profound a villain as Hackman but an extremely memorable character.

Klaus Kinski in The Great Silence is in the top 5, Eli Wallach and Lee Van Cleef in The Good, The Bad.......are up there too

Hackman's an interesting case, because I'd argue that technically, Eastwood/Freeman (and to a lesser extent, Harris/Woolvett) would be the villains of the piece in a traditional Western. Little Bill, though a brutal thug at heart, is actually trying to maintain law and order and does have a sense of justice of his own. It's part of what makes Unforgiven such a brilliant deconstruction of the genre. One of the key themes of the movie is that Eastwood's character is coming to terms with the fact that no matter what, he can't escape who he is. The final exchange with Hackman proves that.

But for the sake of convenience, I'll just stick to the definition of "antagonist" rather than "villain."

Eli Wallach, The Magnificent Seven
Lee Marvin, The Man Who Shot Liberty Valance
Eli Wallach, The Good, the Bad, and the Ugly
Lee Van Cleef, The Good, the Bad, and the Ugly
Henry Fonda, Once Upon a Time in the West
Bruce Dern, The Cowboys
Gene Hackman, Unforgiven
Michael Biehn, Tombstone
Danny Huston, The Proposition
Ben Foster, 3:10 to Yuma

I'd also give a shout-out to Robert Carlyle in Ravenous: not a traditional Western, but a terrific frontier picture.

EDIT: If I considered There Will Be Blood a Western in the traditional sense, obviously DDL would be #1 here, but I don't really think it is. It's got elements of the genre, but I think it's more of an epic story that happens to be set in California, rather than playing to the conventions/traps of the genre. If anything, I'd argue Gangs of New York is a more traditional Western if we're talking DDL films, as Scorsese stated he deliberately tried to make a Western set in the Five Points. I also left off No Country for Old Men because even though it's a neo-Western, I wanted to stick to traditional entries in the genre.

You think so? I'd argue that Stephen Lang's Ike Clanton was even more of a villain than Curly Bill was. Boothe is immensely fantastic in the role, had great gravitas . . . but he kinda becomes the villain through circumstance. He's an asshole, but there are moments where you can see that he acts more as the devil on the shoulder of someone like Johnny Ringo or Ike than anything else. When he shoots Fred White while drunk, he's actually remorseful, and while he does have those golden moments like telling Wyatt "bye," I think it's just Boothe's natural presence that lends those moments more weight than I think Curly Bill actually has.

Biehn is the film's real villain, though. He's something of a dark doppelgänger to Doc Holliday, well-educated and skilled with the gun, with an apocalyptic worldview who sees himself as hell's own emissary. And Lang is superb as the rabid lap-dog, the cowardly cur who will bite when your back is turned. All three would make worthy mentions, but I stuck with Biehn because you scarcely saw him this good before or since.

EDIT: I want to add one little detail about Tombstone that I think really helps to make it such a special entry into the genre. Observe the way the Cowboys treat the effete Jason Priestley character. Most films would have him be derided, belittled, mocked. But Curly Bill and the others see him as a little brother of sorts to be protected, and when they see Billy Zane and realize that Priestley is smitten with him, they don't just accept it, but applaud it. You wouldn't think these rough, uncouth bullies would give a damn about Shakespeare, but because Priestley is in love with Zane, they give it a chance and they seemingly take to it. I always liked that.

All the best have been mentioned. I'll add a recent one Jeff Daniels in Godless and a favorite of mine Burl Ives in Day of the Outlaw:

Ives' performance is really great as the fearsome leader of a group of bandits, yet he's afraid of his own gang, what they're capable of, and he's slipping, he's all busted-up and wounded so he's dealing with literal physical pain under a greater weight of losing his command and purpose.

Day of the Outlaw is a very good pick, those late 50s Westerns are fascinatingly complex. That 15 year run from late 50s to early 70s really sets up everything pre-revisionist, psychologically complex, and then outright revisionist. There's a lot to choose from including the one I've mentioned Kinski in The Great Silence - which is like a billion things at once. It's always fascinating to me when people go backwards with Westerns because that era is ...............f'n awesome