Katy Perry's "Firework" is perhaps the most ubiquitous Fourth of July anthem of modern times. Interestingly, it was co-written by a movie star who appeared in a popular movie trilogy.
Britney Spears' "I'm a Slave 4 U" is one of the most important songs of her career. It's also the most horribly misguided and offensive moment of her career.
Britney Spears' 'Blackout' includes some of her most experimental songs. The "...Baby One More Time" singer said recording a track from 'Blackout' made her feel spiritual.
Britney Spears was often dismissed as a disposable pop star whose songs would be forgotten. Years later, it's clear that the singer produced some of the best dance tunes ever.
Madonna's songs are often forces of personality with no room for anyone else. However, when the Material Girl works with others, she tends to bring out the best in them.