I strongly recommend looking at the other answers to the question: <a href="http://www.quora.com/Whats-the-most-epic-photo-ever-taken" rel="nofollow">http://www.quora.com/Whats-the-most-epic-photo-ever-taken</a>
There are really great pictures in this thread.
I'd like to add this one: <a href="http://www.probell.com/photo_exhibit/Muhammad%20Ali%20vs%20Sonny%20Liston%20(1964).jpg" rel="nofollow">http://www.probell.com/photo_exhibit/Muhammad%20Ali%20vs%20S...</a>