Fleur Delacour was my favorite character in The Goblet of Fire, just because she was pretty and awesome and probably a bitch. She was played in the film adaptation by Clémence Poésy, who did not disappoint.
In my opinion, the BEST part of the outfit is the hat with the jaunty little Dairy Queen-esque curl, sort of a mix between a powder blue Hershey's Kiss and a cartoon ghost tail. But I'm also partial to capes, oxfords, powder blue, girly outfits, multi-layered collars, and pretty dresses.
I've had enough of online-lust-shopping for generic anime cosplay uniforms: someone please make me this outfit, complete with the cute-as-hell little hat and I'll be your friend for life.