I'm a John Wayne vote. Probably second Audie Murphy. Maybe they're tied. I never cared for Audie's movies, but his real life exploits were heroic enough that they get him on ANY tough guy list WAY up at the top. But, if you have to restrict it to movies I'd have to say Wayne's characters were better and tougher, and they always set a real good example to live by.
He still made movies and did his own stunts well into his 2nd bought with cancer in his 70s, you know the one that killed him after his last movie about an aging gunfighter dying of cancer called The Shootist. If you don't think simply making that movie in that situation is tough you have no right judging the contest. Heck reading that script all the way through had to be tough as hell, and he went on to make the movie. Granted I've strayed from physical toughness into emotional toughness, but the 2 are inextricably linked. You simply can't have one with out the other, and especially in his later years he had both in spades!