I like Hingis so much more; Kournikova has the media appeal and celebrity, but I always see her as some young kid with a young face - a girl (attractive, yes). Martina, on the other hand, is just and always has been, a beautiful woman, and a top-notch athlete to boot. She has an allure, while Kournikova, for lack of a bette descriptor, just has her brand-name.
To most men, though, ethier/or is very nice, regardless of choice.