Here's Ollie North's definition of hero:
Heroes are people who overcome evil by doing good at great personal risk. Through self-sacrifice, fortitude and action -- whether they succeed or fail -- heroes provide a moral and ethical framework -- and inspiration -- for the rest of us.
Go read the rest of what Ollie has to say about the our world today. How "evil" isn't evil and "good" isn't good!
Oliver North: Of heroes and hatred