A trio of Oscar-winning actresses strut their stylish stuff on Hollywood's biggest nightNicole KidmanThe Oscar winner is no stranger to drama. Kidman—nominated again for Rabbit Hole, one of 2010’s rawest films—wore a strapless, embellished white Dior Haute Couture gown, topped off by a 19th-century riviere by Fred Leighton featuring 150 cts. of colorless diamonds. Where’s the drama, you ask? The opera-length necklace masqueraded as a choker in the front, but elegantly unraveled down her back, punctuating her outfit with an icy exclamation point of elegance.Opera-length riviere with 150