14. Kathryn Merteuil (Sarah Michelle Gellar) in 'Cruel Intentions'

TV's ‘Gossip Girl’s have nothing on scheming society girl Kathryn, who thrives on manipulation and seduction, and shows no remorse -- even when her schemes end in someone's death. She maintains the illusion of being a perfect role model, until the film's end, when the crucifix she habitually wears is revealed to contain a vial of cocaine.