Sarah O'Connor in the Terminator
Scarlett O'Hara - especially in the book (I agree with Sparrow). Plus - she got to kiss Clark Gable *dreamy sigh*
Mulan - ya gotta admire the girl - she posed as a boy when she knew it could get her executive, and saved an empire. And it's based on an old Chinese Legend.
For a character in a novel - Kahlan from the Sword of Truth series by Terry Goodkind. She's gorgeous, tough, and is smart as a whip. Her strategical thinking saved the day many times. She's married to the hero, but is as valuable, if not more so, as he is. I especially like that the book was written by a man. He must have a strong wife.