Women - I'm relatively neutral on this. 50 year old women who have never cut their hair and allow it to look horrible or grow to their ass..yuck. Basically if it's trimmed and healthy and not greasy or gross, I'm fine with it.
Men - I don't mind a shaggy kind of cut or a little curl. Something like that. Long hair, particularly the kind in a pony tail is awful awful awful. I prefer short hair on men but it doesn't have to be extreme.