To me, the Greatest Cowboy Films Ever Made:

THE SEARCHERS  - 1956   J. FORD
S H A N E          -  1953   G. STEVENS
UNFORGIVEN - 1992   C. EASTWOOD
HIGH  NOON   - 1952    F. ZINNEMAN
RIO BRAVO  - 1959       H.  HAWKS

MAN WHO SHOT
LIBERTY VALANCE - 1962  J. FORD
McCABE & MRS. MILLER - 1971  R. ALTMAN
THE GOOD,  THE BAD,
  THE UGLY        - 1966  S. LEONE
ONCE UPON A TIME
   IN THE WEST -  1968  S. LEONE
3:10 TO  YUMA -             D. DAVES