<first post: woo!>
Way back when, I was thinking of calling in and putting my two cents in for the Harry Potter discussion, but the time passed and I think I missed my window. So, there was a discussion of houses, and this is what I know:
The houses of the school are aligned very directly on the 4 classic Greek elements: Air, Earth, Fire & Water. The whole world was supposed to be made up of these four things.
So, the Gryffindor house is the house of Fire: Think redheads, phoenixes, and many teenage outbursts and tantrums.
The Slytherin house is the house of Water: Natural enemies of the Gryffindors, and the house for potions & and “moral flexibility”. Water will take the shape of its container, of course.
Hufflepuff is the house of Earth, with down-to-earth, likable guys like Cedric Diggory and … not coming up with many good examples here. Diggory, geddit?
And Ravenclaw, the house of Air. Home for abstract thinkers and space cadets. The house for Luna Lovegood, of course.
I don’t think we see much conflict between the Hufflepuffs and the Ravenclaw, but as there is a dramatic conflict between G & S, it seems natural that there would be for the H’s and R’s.