Madonna, "MDNA"

Now in her fourth decade in the public eye, Madonna is an amazing example of creative reinvention and artistic vitality, a consistently innovative performer, singer and songwriter. In America, she was the single best-selling artist of the 2000s, and is set to add to the tally with her latest record which was released on March 23 on Interscope. Also take a listen to "Glee: The Music, The Power of Madonna," a collection of her songs done by the cast of "Glee," all of which were performed on a special Madonna-themed episode.