It depends on the shade, how it looks on her, and whether or not she is sexy. The sexy is unrelated, but if she is sexy and has red hair, then she may be even sexier.
Of Course red heads are gorgeous too.....They actually found that the gene that causes red hair is being eliminated from the gene pool and in the future there won't be any more real redheads. Sad, really.....
Amanda Righetti from the Mentalist is pretty hot too.
I think I Commit it to memory, to reuse on the right occasion.
Men ... not so much ...