Songbird is a desktop media player, specifically designed with the future in mind. While most media players are still focusing on local music only, Songbird is currently looking to the constantly-changing landscape of the web for guidance. What does this mean? Simply put, Songbird allows you to 'play' the web. Instead of needing separate applications to search for and listen to music, Songbird allows you to do it all from one simple program, with an astounding level of integration between the web and your music.
Of course, many of the most popular media players, such as iTunes on Mac and Windows, and Winamp and Windows Media Player on Windows, are available free of charge. But there's more to Songbird's freedom than its lack of a price tag: Songbird is open-source, which means that it is community-driven and powered by you. You can truly make it your own and modify it to your heart's content with add-ons. Also, rather than just implementing the features that are most likely to bring in revenue, Songbird's development team can implement features that they think are cutting-edge, useful, or just plain cool.
Have you ever tried to play music on another operating system, only to find that you are unfamiliar with the media player? That's not a problem with Songbird, since it runs on the 'big three' of operating systems (Windows, Linux, and Mac OS X), which means that you'll have a consistent experience between operating systems.
Songbird is probably the most customizable media player on the planet. Want to change the way it looks, add support for a web service, or add something new to the way the media library works? There's probably an add-on for it, and they are easy to install.