I think when it comes to skin tone it was something to do with your standing or wealth where lighter colored skin in Asia was associated with wealth as they were not out in the fields working all day in the sun and for here the opposite where wealthy people with tans because they were often holidaying abroad.
ofcourse this has now been reinforced by the glossies and the cosmetic company's.
scientifically I think its do with symmetry but there is always exceptions to the rule

http://www.jyi.org/volumes/volume6/i...ures/feng.html

My Wife looks most beautiful in the morning when she is still half asleep cuddle in my arms and hair slightly draped across her face with a comferting smile on her lips.......and shes not talking