Great posts so far, but yeah, this is Hogwarts not public school. Shame on you. Wear your uniforms guys.

I think the reason they dressed well in muggle cloths in the movies was to satisfy the larger audience. Since most would find it easier to watch something familiar. But I agree, it did kill the integrity of being faithful to the book. I expected at least one of the three to be in uniform during the Deathly Hallows, even for half the film. Whatever.