Instead of trying to select the best western, including spaghetti western, I would instead select the 10 best westerns. In no order.
1) The Good, The Bad, and The Ugly.
2) Once Upon A Time In The West.
3) Unforgiven (Clint Eastwood version).
4) The Great Silence (aka “the western in the snow”, an extremely harsh movie with alternate endings.)
5) A Fistful Of Dollars. An unauthorized remake of the Akira Kurosawa film Yojimbo (1961).
6) For A Few Dollars More.
7) High Noon.
8) The Searchers.
9) The Magnificent Seven. A remake of Akira Kurosawa’s film Seven Samurai.
10) The Wild Bunch.
Let me add some standouts.
Rancho Notorious (1952) Dir. Fritz Lang, starring Marlene Dietrich.
The Assassination of Jesse James by the Coward Robert Ford (2007). Underrated, both the direction and acting are top notch.
Winchester ‘73 (1950).
Tombstone (1993).
The Treasure of the Sierra Madre (1948). Though taking place in the 1920s, and as much film noir as western, it still deserves recognition.
Unforgiven is not on your list?