Ashley Parker--Eight-Legged Freaks
Jordan Two Delta/Sarah Jordan--The Island
Olivia Winsome--The Prestige
Silken Floss--The Spirit
Black Widow--Iron Man 2
Black Widow--The Avengers
I was going to include Ghost World as well, since it is based on a comic book, but I figured the definition of science fiction had been stretched enough with The Prestige The Prestige is one of her best. So is Ghost World.
Speaking of stretching, how about that Black widow costume?