LMAO, seriously? She's pure pop music. Yeah she can pull off some urban hits, but its all pop music. Just because she's black and has a soulful voice doesn't automatically classify her as solely being R&B.
Madonna's contribution to music, more specifically to pop music, will remain extremely relevant and will never be forgotten. We can have a million Britneys, Beyonces, Christinas... they'll never be good and significant enough. She's the queen of pop, Michael is the king, period.