I'm a Proud Slytherin and Will Defend The House No Matter What

Finally, let me state the obvious: Harry was supposed to be a Slytherin. If Harry were in Slytherin, he wouldn't have befriended Draco and given himself up for the Dark Lord's cause in the first book. He most likely would still turn out to be exactly who he was, just maybe a bit estranged from his classmates. As Dumbledore said, Slytherins were chosen in part because of their “certain disregard for the rules,” and this defines Harry every bit as much as courage or pride. He might have even been encouraged to be a bit less impulsive at times.