Media Server OS - Sell me on Linux

I want to make a media server out of some older computer parts I have.  You know, just a local network server I can grab music and movies off of from multiple devices.  Is there any reason to go with Linux over Windows?  I have free access to the Windows Server OS through a Dreamspark Premium account, but what's the benefits of using, say, Ubuntu server?

- no DRM

- better network performance

- better filesystem performance

- more compatibility

- no DRM

- oh, did I mention no DRM...