All of them, ya un 'Murican heathen!
But seriously...
I always had a fondness for the ones with a little humor in them. El Dorado, Rio Lobo, North To Alaska, McClintock, Big Jake, et al. Can't argue with The Searchers being one of the most visually beautiful pieces of cinema ever filmed. True Grit is always a good watch, though I have to admit I enjoy Rooster Cogburn a bit more. Too bad the Duke died before he and Katheryn Hepburn could make a couple more movies. The dynamic is just about perfect. Hellfighters is a nice change of pace from the cookie-cutter westerns. Green Berets is decent. Flying Leathernecks is formulaic but enjoyable. Oh, almost forgot How The West Was Won and The Man Who Shot Liberty Valence.
Brad