The Dragoon type boss from Shadow of the Colossus. It had everything to make an epic battle. First, you ride under it as it flies and shoot certain points on it with your bow. Then, as it lowers, you ride up alongside side it, leap from your horse and grab onto it's wings. then you leap into it's body as it goes back into the air, cling to it's hairs as you climb to it's weak spot and thrust your sword into it, purging this vile creature from the land. When you leaped from that dragoon as it crashed lifelessly into the desert, you can't tell me you didn't feel like a fucking GOD!
Man, that fight was awesome
EDIT: Is it fair to say that Shadow of the Colossus was just an epic game, by definition, full stop?