Okay, found the thread.

I think that Aang's humble and caring personality is the best thing about him. The person who called him a "Luke Skywalker type hero"got it spot on. The reason that heroes like Aang and Luke stand out is not just because of their personalities (or the fact that they kick ass) but also the way they treat their enemies. How many heroes from other stories, when having emerged victorious from a life or death struggle with their greatest enemy, an enemy they know to number among the truly evil, would still be willing to extend mercy to them, to stand by their belief that all life is important, and that anyone can be capable of redemption? I really don't think that there are many examples.