I think that Madonna is amazing. Love her.
Love the album confessions on a dancefloor. Just didn't like the albums erotica and bedtime stories.
But she gives great shows and is a real entertainer. Yes, her voice isn't the best, but much better since Evita. And she isn't the only one

The hole package is awesome, that makes her the queen of pop. And she deserves it, worked hard for that.
But everybody got's his or her own opinium about that. And Freddy and Prince are also very good artist. But there will be always people who would disagree.
One likes Madonna, the other one Prince and the other one Rolling Stones.
But there are all big stars, who are huge and give great performance.
So I don't think there is just one the best and the greatest.