Each house described by a Princess Bride quote. Ravenclaw: "Let me put it this way, you heard of Plato, Aristotle, Socrates?" Slytherin: " 'Surrender' 'You wish to surrender to me, very well I accept'.
Sirius and Hagrid were! Hagrid should not be forgotten, he did so much <<< Don't get me wrong, Sirius was very much a father figure to Harry and he was very important (also, I love Sirius) but we shouldn't forget Hagrid.