I watched the new version of True Grit the other night and what a disappointment! I think they were trying to be accurate to the book (I haven't read the book in probably 25 years), but it was awkward and mechanical.
John Wayne may have been a character actor, but he played that character very well. Same for Clint Eastwood.
Here is my list in no particular order.
McClintock (Western adaptation of Shakespere's "Taming of the Shrew")
Quigley Down Under
True Grit (John Wayne version)
The Good, The Bad and the Ugly
Ook ook, for Once Upon A Time In The West. The opening scene of that is as good as any western gets. "Did you bring a horse for me?" And the second is almost as good. "Now that you've called me by name..."
Once again I agitate for The Wild Bunch.