When I was at primary school, there was a quite strict uniform of a white blows (not a PE top) a navy skirt and a navy v-necked jumper with a school tie. This was very smart and reasonably cheep, as you pay loads for those sweat shirts with the logo on and they just look slouchy. Somthing you'd ware for lazing around the house in.
When my daughter starts school, she'll wear a lovely white crisp blowse and a nice pinnafore, but it will unfortunatly be ruined by a chunky sweat shirt over the top. I don't think they are any more practicle than a cheeper wool jumper that looks smart.
People always complain about the cost of uniforms but I wouldn't mind paying for the jumper if it looked smart.