Hands down, no competition.
It's one of my favorite westerns ... and you can't find a DVD/VHS of it for love or money...
The movie? The Wonderful Country with Robert Mitchum.
I have spent time north of the border in that area ... and between the heat, dust, scorpions, tarantulas and rattlesnakes (including the two legged kind), I can honestly say I never want to visit the area again.
But the director and filmmakers obviously loved the country ... and watching the movie almost makes me change my mind ... *S*