You might want to make the title and the poll title coincide.
My least favorite color is dyed, because if it's not your actual hair color, why does it matter? (I dislike fakeness in general, including fake tans, make-up, and excessively groomed hair)
But otherwise I have no preferences. I would say bright orange has more potential to be stunningly beautiful (there's just something entrancing about a pretty girl with orange hair and a leafy-green background), and blond has too many stereotypes attached to it (dumb, slutty), but when it comes down to it, I don't really prefer one color over another.
I used to prefer blond, but virtually anything slutty girls do (fashion wise) I instantly find repulsive, so it dropped down to the same level as everything else.