There are times when I like to have some background music playing on my PC as I am catching up on email. If you have not stumbled upon Pandora you really should give it a try. Pandora leverages the Music Genome project. This project, created in January 2000, is an effort by a group of musicians to capture the essence of music at the fundamental level.
Pandora will ask you for a favourite artist or song and it will build a radio station to your musical preferences.
Custom radio via Web 2.0.