Clint Eastwood is definitely on to something here. You know, until I saw the Dollars, I never understood what a lot of people see in superheroes (like Superman, Batman, etc.). The man with no name is a superhero. More realistic than the comic superheroes, but a superhero nevertheless. He's lightning fast and deadly accurate with a gun, he's smart, shows very little emotion, doesn't talk much, he's alone and sulf-sufficient. As a man I find those qualities appealing.
I don't see as much superhero in Harry Callahan as I do in the man with no name, but Harry does posess a lot of the same qualities.