Superman - Superman
He's an alien, but so are a lot of us. Superman remains one of the greatest symbolic expressions of the American immigrant saga, starting with a very mild-mannered name change from his ancestral Kal El, to moving to the big city, to working his ass off at two jobs - both as a tax-paying freelancer. Clark could have settled down anywhere, really (and in one alternate universe, he did). But he stayed put because he believes in what the U.S.A. stands for, what it promises to be. Being born in America is not a prerequisite for being among its greatest champions.