Is beauty really in the eye of the beholder?

I agree there are different cultural standards for beauty but at the same time there is a plenty of similiarities in the standard of human physical beauty. Is this a just a saying that people use to make everyone feel good? How come some people are more appealing than others? More guys would choose Megan fox over Paris Hilton. More guys would choose Kim Kardashian over Hilary Duff probablly. More girls would choose Will Smith over Jack Black.