Music Player Daemon (MPD)
http://www.musicpd.org/

Music Player Daemon (MPD) allows remote access for playing music (MP3, Ogg Vorbis, FLAC, AAC, Mod, and wave files) and managing playlists. MPD is designed for integrating a computer into a stereo system that provides control for music playback over a local network. It is also makes a great desktop music player, especially if you are a console junkie, like frontend options, or restart X often.