Being Saved by Our Guardian Anglia
Uniforms (aside from Quidditch uniforms) are never actually mentioned in the books. That's all from the movies (and based on Muggle boarding schools).
The only thing ever mentioned in the books, I believe, are robes. Presumably kids wear something under the robes, but it might be nothing more than long johns, slips, undershirts, that sort of thing. (Remember when wizards are described wearing Muggle clothing, they usually get it disastrously and comically wrong, suggesting that unlike in the movies, most wizards aren't even familiar with things like jeans and T-shirts.)
When they go to the Yule Ball, they don't wear gowns (or saris ) like in the movies. They wear "formal robes," which I assume are like regular robes except more colorful, more frilly, with more decorative trim, multiple layers, and the like.
So movie Draco, who wears sports jackets and suits, is completely non-canon. I seem to recall a few illustrations in the books where Harry and Hermione are wearing what looks like jeans and sneakers, but they were both Muggle-raised, so they probably wear what is familiar to them, when not in robes.
But uniforms? Nope. I think Houses are only distinguished by the color of the robes they wear.
Book four of the Alexandra Quick
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In PS or SS, on the uniform list, Harry is asked to bring a black pointed hat, and black robes. There is no mention of anything else (apart from a cloak and gloves). In GoF, Harry is said to empty out his trainers when he arrives in the Great Hall. This probably means that this is regular footwear, though I imagine people like Hermione - or Draco - would wear black shoes. This is just what I think.
In GoF, a wizard at the Quidditch World Cup, says, when asked to take his dress off, "I like a healthy breeze round my privates, thanks." This might have nothing to do with him wearing robes most of the time, but I think it's worth the mention.
Mugglenet Uniform Information
Also, googling 'hogwarts uniform', the first page has a few good links.
Hope I've helped!
Quote from Chapter 7, pg 77, UK Edition of Harry Potter and the Goblet of Fire
Yes, the 'uniforms' in the movies are not necessarily canon - at the very least, the sweaters, ties, etc. aren't mentioned as being in the books. (It has, however, become one of those things that is so common that people don't really think nothing of it.)
The robes, though, are all BLACK; they're not different colours. Perhaps there is a patch or something (like in the movies), that denotes what House a student is in - or there's is nothing that denotes a Ravenclaw from a Gryffindor. (Remember, there's that scene in CoS, I think, when Harry and Ron are Polyjuiced as Crabbe and Goyle. They run into a girl while looking for their common room, and mistake her for a Slytherin (she's actually a Ravenclaw). That sort of gives the idea that all the students are strictly in black robes, with no denotation of House affiliation whatsoever.
As a reader, though, I tend to overlook the fact that a writer uses the 'movie' uniform to dress the students. BUT, if you want was is strictly canon in the books - Black robes are all that is mentioned (and a hat).
Okay, thanks a lot! That was a lot of help. My beta pointed it out and I wasn't sure what to do about it. You've helped a great deal
Snape Hates Me
One other small bit of canon information on the subject is from Snape's Worst Memory. When he is hoisted in the air upside down, his robes fall over his head to reveal his pale legs, I believe, and "graying pants" and in Britain, pants are underwear. Poor Snape, how humiliating.
So, they are definitely dress like robes and not slacks or anything. Still, I'm with megan lupin, I don't really mind the movie style uniforms, so long as they have the robe/cloakish thing. Actually, to be perfectly honest, I prefer it and use it myself.