Pulled the old trope image because it was attracting a bit too much natter and put a shot of Kaworu from the new Rebuild Of Evangelion trailer in place. I hope we can all agree on him to be the quintessential white-haired (okay, Depending On The Artist) anime bishonen?

The Elric-ish villain from Game of Thrones miniseries, who sold his sister off to the Conan type.

Couldn't the Red Mage from the original Final Fantasy be thought of as a White-Haired Pretty Boy/Girl? Between his/her style of dress and, of course, his/her long white hair... Though, since s/he is a Warrior of Light, s/he is never a villain...