I would say Madonna because there's other references that use that name as their own except I think Britney wins this my a mile and I'll explain why. She was successful in making it her own name and having people recognize her solely by that name and not by her real name. However, Britney was successful in making herself known with two names while Madonna is known mostly just as Madonna. I mean the world doesn't really call her by her real name. Britney is refereed to as Britney Spears or just Britney. Everyone knows who you're talking about just by the name Britney and that says a lot. Rihanna is also a great pop name. Beyonce is a very getto name and isn't really pop. When you hear it you think r&b and that doesn't work for me.