Okay, I'm buying your Superman argument, though he's always seemed to be very Gryffindor to me: stereotypically so, which is how he and Batman come to so much grief with each other whenever Superman tries to use Metropolis tactics in Gotham.

Then again, your point that he not only founded the JLA, but convinced Batman to play on his team, is a very good one. Though I don't actually think there would be a gathering of the spandex crew's Major Players that Batman would miss, because that's too much concentrated potential power for -- he's got to get invited to the asskicking party keep an eye on it.

Tenacious loyalty, anyway, which puts him in either Hufflepuff or Gryffindor, depending on his reasons. I guess I just don't see him tending to work with and through other people as much as, say, Nightwing does, but he definitely fights because he identifies himself with a group of particular people -- and Luthor is his archenemy because he's trying to deny him of his humanity and his place with those people.

So, maybe, yeah. :)