My kiddo goes to a uniform optional pubblic school, and I love it. Monday's and Wednesday's are "uniform days" they encourage the kids to wear "uniforms" these days. There uniforms are pretty lax, the color options are Khaki or navy blue for the pants/skirts/jumpers and white, navy blue or teal for the tops. There is no catalog to order from or anything, just anything in these colors works. My daughter LOVES to wear uniforms, she looks forward to "uniform days", I keep waiting for her to grow out of it, but she is in 3rd grade and she still loves it! Friday's at her school are also "school pride" days, in which the kids wear either a uniform or a school t-shirt, etc.
This works well for us, as Monday, Wednesday and Friday the kiddo is basically in a uniform, without the normal distraction of clothes issues and still gets to express her individuality on tuesday and thursdays..