Easily the best dress on film in the aughts, this floor-sweeping, slinky '40s evening gown by designer Jacqueline Durran had audiences green with envy. As Cecilia, Keira Knightley wore this tantalizing emerald backless number with spaghetti straps, a wide gathered waistband, high front-slit and perforated neckline in the super-sexy scene against the bookshelf with James McAvoy. A jewel of a gown, it's enough to make us renew our library cards.
Sharon Stone perfected minimalist, '90s chic in this crisp, short shift dress with a roll-neck and high-cut armholes when she made a quick, provocative wardrobe change before going downtown for police questioning. Made of winter-white wool crepe by Ellen Mirojnick, its innocent color became anything but during an infamous interrogation scene that left undergarments at an, er, minimum.