This is a hard question to answer, since female celebrities are constantly changing their hair color. I have to say that when Lindsay Lohan was younger and still had her natural red hair, she looked beautiful. Now she looks like the south end of a horse going north.
Nicole Kidman is an excellent choice! Recently, I noticed that she's returned to her more natural hair color, sort of a dark strawberry blond. It looks much better on her than when she was sporting a lighter blond shade.
My favorite, besides me....Isla Fisher