I read an article about this a while ago..
Apparently 11,000 years ago all Europeans had brown hair and brown eyes. A genetic mutation caused some women to be born with blonde hair. There was a large population imbalance between men and women, with more competition on the women's side to find one of the few men. Blondes were seen as more desirable and therefore more men mated with blondes, hence passing down the blonde genes and eventually spreading all throughout Europe.
Blue eyes are thought to be a genetic mutation from inbreeding.
I guess guys are wired to like blondes