School uniforms are just another inconvenience to adolescents' lives, just like parents, and rules, and the inability to simply do what they want.
Yes, while I agree that its sad that school is molding our kids to becoming more puppets of consumerism and capitalism and societies standards, I also believe it's a necessary evil.
I love how so many posters here are appalled at this concept, as if no one ever has to wear a uniform or adhere to a somewhat strict dress code for a job. Unless your self-employed, work as some kind of entertainer, or have a job like a tattoo artist or musician, you're going to have to wear some kind of uniform to make a living. Get used to it.
I'm all about self-expression, but I realize that clothes are just an image, if I'm denied my own choice when it comes to them, then I'll find other avenues of expression, I have to have something. Hell, being in the army I'm very limited when it comes to that, but I went out and got the one pair of boots I've never seen anyone wearing, just to have something to call my own. If you absolutely must have your own thing going on, there are ways.
All in all, I guess I'm for school dress codes and uniforms. Sure they have no impact on your learning but thats no the point, school molds you for society, and not just in an academic way. The faster kids realize that they will have no control over some things in life, the faster they will mature to not give a shit and move on.