I guess it depends on what ones definition of an anal pornstar is. So many do anal but I wouldn't call all of them perfect. It would have to be a pornstar who includes anal in the majority of films and in the scene have anal for more than 50% of the scene. They would have to be able to take big cocks too and look hot.
My vote has to go to Aurora Jolie. Hot natural girl, big tits, sexy ass.... and all she does is anal (no pussy fucking)