On the red carpet, these stars shined. Gwyneth went minimal metallic in Calvin Klein, Florence Welch was the picture of vintage-inspired femininity in Valentino Couture, Celine was polished and elegant in Armani Privé, and Mandy wowed in a sparkly nude Monique Lhuillier gown. Onstage, it was a totally different story. Florence got more fiery, Celine stayed polished, Mandy turned blue, and Gwyneth went nude. Who gets your vote for best onstage outfit?