even though i'm not sure if you could call it a school uniform since everyone seems to wear just whatever the heck they feel like at that school, i think it still looks enough like the traditional ones to pick it.. so in that case it'd have to be the one akari wears from genei wo kakeru taiyou, it's so cute.. i love the colors and the ruffles and the striped socks really make it, tbh.

(of course i'd pick a magical girl series)