Although Butch Cassidy and the Sundance Kid is a great film, Tombstone is without a doubt my favorite western. I just really connected with the characters and loved the story. I guess it's a timing thing too because the movie came out when I was about to turn into a teenager. Doc Holiday was an educated man who knew about Chopin's Nocturnes and spoke Latin and Wyatt Earp was a classy law dog with balls of steel.
Almost nobody I talk to mentions 3:10 to Yuma, I thought it was a great film so I'm glad you gave it an honorable mention.
RE: A Geeky Guy's Guide to Westerns