Britney is already one
Beyonce will be one at this rate
GaGa has the potential to be one definitely
Rihanna I really dont know...like someone else said I see her being more iconic than legendary...but what you fail to realize is that Rihanna has yet to show us her full potential. It has come out in glimpses and peeks (Rated R, AMA performance) but Rihanna seems to have a lot left up her sleeve, and if she was to hone her potential she would be a force to be reckoned with. Don't count her out yet