1. The Good, The Bad and the Ugly (1966): The ultimate Spaghetti Western and in many ways the ultimate Western. You've got three men, Clint Eastwood, Lee Van Cleef and Eli Wallach playing cat and mouse as they pursue a buried treasure in a grave. In the process, you have iconic moments, a twisting game of revenge complete with last second reprieves, beautifully staged gun fights, and one of the greatest scores ever in a film. I can watch this one every day.
2. The Magnificent Seven (1960): This film is just fantastic. A remake of Seven Samurai (another excellent film), you got seven big named action stars teaming up to take on Mexican bandit Eli Wallach. What makes this film so great is that it explores each character, including Wallach, and you come to like (or pity) them all, including Wallach. Add in snappy dialog, scene stealing Steve McQueen, and a booming soundtrack and this is easily the best classic Western you will ever find.
3. The Wild Bunch (1969): If the The Good, The Bad, and the Ugly was a story about antiheroes, then The Wild Bunch is simply the story of villains. One group of villains robs a bank. Another group of villains is hired to stop them. They chase them to Mexico where they encounter villainous Mexican soldiers. Directed by Sam Peckinpah, this is "tough guy" Western at its peak. It's brutal, it's bloody, and it's packed full of action and, of all things, philosophy.
4. Silverado (1985): This is a great redemption story done with tremendous ability. Interesting characters with strong relationships, great actors, some great situations, some likeable villains, and a plot that pulls you in and keeps you going from start to finish, I highly recommend this film.
5. High Plains Drifter (1973): This one's really fascinating. This is the story of a man with no name, Clint Eastwood, who may well be an avenging angel come back to town to punish the townsfolk for hiring killers to get rid of their sheriff and then watching as these killers whip him to death. Interestingly, this was remade by Eastwood in the 1980s as Pale Rider, and while Pale Rider was a good film which I enjoy very much, it completely lacks the spirit which made this film so special. This film feels like a glimpse into hell at times.
6. Dodge City (1939): If there's such a thing as a cliché Western, this is it. Errol Flynn needs to clean up Dodge City to make it safe for the good people who live there and in the process, he fights cattle barons and gunslingers. But this cliché is done right!
7. Blazing Saddles (1974): Funniest... western... ever.
8. Unforgiven (1992): This film pissed me off originally. The first time through, it felt like Eastwood was repudiating his Spaghetti Western days. But over time, I've come to see this as a film that wants to be a more serious, realistic Western, but at the same time lets us know that The Man With No Name lives in Eastwood's spirit and he'll come shoot every last one of you if you give him cause.
9. The Quick and the Dead (1995): I'll admit it, I like this one. This film was meant to deconstruct Westerns and essentially mock them. But it's got an amazing cast and it soft-pedaled the satire a little too much to achieve its purpose of sending a nasty message about Westerns. Thus, what was meant to be smug and condescending actually turns out to be a heavily-clichéd but fun Western... a serious version of Rustler's Rhapsody mixed with Bloodsport and I enjoy it.
10. High Noon (1952): This is a very uncomfortable Western because everyone is made out as a coward, a hypocrite or a monster. Nevertheless, the story is made with undeniable quality and in the end you feel satisfied when the Marshall saves the day and then walks away from the townsfolk he once thought were decent people. In a way, this is a revenge fantasy where Cooper proves everybody wrong and then shames them by leaving them to wallow in the own cowardice and avarice.
Let me also give a shout out to Sergeant Rutledge. This is a really well done film that handles race and racism in the US better than any film I've seen in Hollywood. It's also a fantastic legal drama.