Madonna is in the Rock Hall of Fame so like you say it probably should be just popular music. But "rock" is so broad anyway I don't know where the lines are....probably somewhere right around Neil Diamond... (just kidding all you Neil Diamond fans...)
I think I'm gonna buy Lilo Neil Diamonds Greatest Hits for his birthday, so he can hear some real R&R.
TIS
"Mankind must put an end to war before war puts an end to mankind. War will exist until that distant day when the conscientious objector enjoys the same reputation and prestige that the warrior does today." JFK
(just kidding all you Neil Diamond fans...) 
