From what I've seen many pop singers do pink in their hair. Avril Lavigne for one (she's kind of obsessed with pink from what I've seen eek). And there's some other pop singer called Skye Sweetnam that has pink streaks and also another one, Joss Stone. Don't know why but every woman celebrity that does an unnatural colour in her hair, it's pink. Probably following the trend of trying to be more "rebellious" while still being girlish?
I just saw Lilly Allen with pink hair, didn't know she had it like that. It doesn't really suit her, she's too tanned for such a light pink. And that dress is just awful.
And, yeah, Cancankant, I agree about Pink and I think Gwen Stefani looked better with pink hair than with blond. And also that green wig really suited Angelina Jolie.