I have worked at both uniformed and non-uniformed schools. It was so nice having uniforms since the pants were required to be on the hips, shirts tucked in, and belts worn. I never had to look at boxers or thongs hanging out, although some of the young ladies purposely purchased shirts too small so their "girls" could be counted as present as well. The school admin stood out in the hallways before and after school as well as between classes to check for violations--teachers weren't made to focus entirely on that aspect of the school day. The school store sold shirts for $10 a piece, and they bought back shirts to be sold on the "As Is" rack when students graduated or transferred. These clothes were sold at a discount, so it was never an issue for parents to clothe their students. Any khaki or navy pants, shorts, skirts (no denim) were acceptable as long as the length was appropriate (shorts and skirts were to be no shorter than 2" above the knee).
Hair styles (color had to be "naturally occurring in human nature"), belts, jewelry, shoes and socks were not regulated and could be any color or style. This is where students expressed individuality. Of course, there were days when students could pay $1 to wear everyday clothing for fundraisers and we always made a mint on those days.
One of the senior superlatives was "Most Creative Uniform Embellishment". They didn't seem to mind the uniforms as they always knew what they were wearing. It made for some good jokes when picture day came around, though. :)
Our students always looked nice, were focused on academics, and in all four years I worked at that school, there was not one instance of teen pregnancy. Don't know if uniforms were the reason, but it's an interesting observance.