Jeremiah johnson
butch Cassidy and the sun dance kid
new 3:10 to yuma
maverick
the quick and the dead
good bad and the ugly
both true grit
Tombstone
Wyatt Earp
Lonesome dove

almost any Eastwood or Duvall movie

and while I wouldn't classify it as a western I love No country for old men, ranks towards the top of my favorite movies all time.