Madonna, "Celebration" (Warner Bros.): How do you say goodbye to your label home for the past 25+ years? With a greatest hits package that, even at a walloping 36 songs (34 classics and two new tracks), still doesn't cover all your hits. Configured lots of different ways-single disc, double disc, CD/DVD combo... Madge any way you want her. The title track just became Madonna's 40th (you read that right) No. 1 on Billboard's Hot Dance Club Play Chart. Catch her on David Letterman on Wednesday.