This album is the crowning achievement in Madonna's career. There was a lot of controversy surrounding this album, particularly in relation to the videos for Like A Prayer and Express Yourself (which happens to be one of the best videos ever made). This controversy never hurts sales, and Madonna shrewdly used this fact to her advantage on more than one occasion.
All the publicity surrounding the videos didn't hurt album sales, but this album would have sold truckloads of copies anyway, because the songs themselves are phenomenal. Like A Prayer has more than just the great video going for it. The song is amazing. Express Yourself is one of the best dance tunes ever written, and you can just picture her writhing on the floor with chains wrapped around her neck when listening to it. Cherish is a delightfully light-hearted and feel-good tune. Other notable tracks on this album are the incredible Oh Father (the best song on the album), the stunning Spanish Eyes, and Promise To Try.
If you don't own a Madonna album (and if you don't, shame on you) and want to try one, this would be the one to try. Ray of Light and True Blue are also highly recommended.