Madoka Kaname for me!~ ~*Spoilers below, my friends!*~
She gave her very existence away to reset life and end the suffering of her fellow Puella Magi around the world and throughout time, becoming a god of hope. Pretty heroic, I should say!
Touma Kamijou ~He goes to great lengths to save someone he barely knows. He doesn't really need a reason to fight for someone, when he sees someone in trouble he just help them even when they don't ask for his help