Google Play Music Desktop Player - A beautiful cross platform Desktop Player for Google Play Music
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
GDeskTunes - Multi Platform Desktop Player for Google Play Music™ that integrates beatifully in your OS.
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.
Nuvola Player - Cloud music integration for your Linux desktop.
Maloja - Simple self-hosted music scrobble database to create personal listening statistics.