Bjork ripped off her look her by wearing Japanese clothes to seem futuristic and edgy (yes, they're wearing purple Japanese clothing in the video below) and M83 ripped off the song with Midnight City.
Britney needs to retire. I'd suggest a long break, but is it worth her coming back when she's pushing 40? She'll probably have even less drive by then, even less physical ability to dance, etc, and by then she'll probably look 60. And do we really want to be hearing her sing about dancing on the floor or whatever when she's 40? She never grew artistikally past a teen pop/sexy image, a genre whose returns diminish the older you get. She needs to live ha life on her own.