Shmplayer executes a single instance of mplayer in the background and controls it through a FIFO. It supports many of the features you'll find in XMMS and it is easily extendible. However, unlike XMMS, shmplayer doesn't require an X server to be active. You can even use it from a remote shell. Shmplayer has also some unique features like "jgrep" that lets you jump to the first "grepped" match of the playlist.
SlimServer on DiskStation is an add-on package to the Synology DiskStation family of PowerPC and ARM9 based NAS devices providing the environment to run SlimDevice's SlimServer on it. It integrates into the DS administrative Web interface and comes with various user-friendly tools and scripts to maintain the installation. It supports all currently official features of Slimserver, such as Asian character display and on-the-fly transcoding of various music file formats. Popular third party plugins are supported as well.
Plait (pronounced "play") is a command-line jukebox and music player front end. It understands brief, easy to type queries that pick a single song, mix queries that combine works from multiple artists, and stream queries that find Shoutcast radio streams. A variety of filters are available to pick just the music you want to hear. In order to actually play the music it finds, Plait automatically hands off a playlist to one of the supported music players, or creates a playlist that you can manually load.
mp3cleanup is used to tidy up various aspects of MP3 files, including filenames, ID3 tags, path, m3u playlists, and bitrate. This is particularly useful for hardware MP3 players that sometimes have arbitrary limitations on the files they work (well) with. It can operate on single files or on all the files contained in a directory.
burnCDDA is a console frontend to cdrdao, cdrecord, MPlayer, mpg321, oggdec, mppdec, flac, normalize, and mp3_check. It can be used to create audio CDs from an M3U playlist (the playlist format of XMMS and amaroK) or from files inside a directory. It supports MP3, OGG Vorbis, Musepack, FLAC, WMA, M4A, and WAV files, and it might be the easiest way to copy an audio CD.
abcde is a frontend to cdparanoia, wget, cd-discid, id3, and your favorite Ogg Vorbis (the default), MP3, FLAC, Ogg Speex, or MPP (Musepack) encoder. It grabs an entire CD and converts each track to the desired format, then comments or ID3-tags each file, all with one command. It supports multiple output in a single CD read, the creation of a single track from a CD, resume operation, CD concatenation, volume normalization, gapless encoding (with LAME), parallelization, SMP, proxies, customizable filename organization and munging, playlist generation, distributed encoding via distmp3, and more.