I'm a huge fan of the Duke so in addition to those already mentioned,

Chisum
The Sons of Katie Elder

And my all time Favorites
Big Jake
The Shootist

But to be honest I love Westerns and I am a huge fan of Clint Eastwood, Sam Elliot, Tom Selleck, Kevin Costner and Robert Duvall as well, all of them, spaghetti westerns what ever I love Westerns, I mean who doesn't have to watch Dances with Wolves, I loved Tombstone but I also loved Wyatt Earp.