The Costume Institute Gala was full of famous faces in NYC last night, but the ladies were the stars of the red carpet. From their gorgeous gowns and stunning makeup to their hot dates and high heels, there were plenty of women to watch. Some sexy stars really steamed up the event, including Diane Kruger, who showed lots of leg in a slitted Jason Wu gown. Rihanna's see-through lace number by Stella McCartney left little to the imagination, and Gwyneth Paltrow's backless Stella McCartney dress perfectly hugged her hot frame. Kristen Stewart wowed in a sultry crimson Proenza Schouler, while Beyoncé Knowles showed cleavage in a daring Pucci, and Blake Lively went with a sheer Chanel creation. So, tell us — which of these ladies do you think was the sexiest of the night?