1. Far and away El Dorado is my favorite. Saw it in the theater in 1968 on the big screen and maybe 30 times on TV since then. Michele Carey in her tightly stretched top and leather pants perhaps responsible for most of my impure thoughts as a teenager.
2. The Man Who Shot Liberty Valance. John Wayne, Jimmy Stewart and Lee Marvin. Doesn't get any better than that.
3. The Professionals. Not quite a true western as it is set in the early 20th century but it has the feel of a classic western tale. Marvin and Lancaster and others make a great cast.
4. The Unforgiven (Eastwood version). Gritty, dark and brooding it feels like the reality of killing is being displayed. Great portrayal of the brutal marshal by Gene Hackman, one of the great character actors.
5. Winchester '73. Jimmy Stewart once more in a great story.
Honorable mention nods to Silverado and The War Wagon.
For comedy relief, Cat Ballou (Marvin wins Oscar and it has a great soundtrack).