My school has a dress code. Can't wear any items deemed 'inappropriate' by the staff and all shorts/skirts have to be at or below the kneecaps. You also can't have your shoulders exposed or really low-cut shirts.
So basically it all affects the girls, not the guys.
That's what we have, although the only people who really pay attention are the Principal and Vice Principals.
Yeah, it really depends on the staff-member if the dress code is enforced or not. Some staff could care less, while others are borderline Nazi on the enforcement.
I don't really like the idea of school uniforms, though a dress code like that would be ideal. Kids shouldn't be allowed to wear distracting clothes, but they also should not be forced to wear fascist uniforms.