AmpJuke makes it possible to manage and stream your music online to several clients connected through a LAN or the Internet. In addition to streaming music, it can fetch "metadata" (album covers, images, lyrics, and track "fingerprints") automatically using various Web services such as last.fm and the.echonest. You can scan and import tags from as many tracks as you like, use favorites, and customize personal settings. Its focus is on easy navigation as well as speed.
BallroomDJ is a ballroom music player. It is designed to let the computer choose the music and to be able to play music the entire evening without intervention. It features flexible playlists, music queue management, requests, seeking in songs, speed with pitch control, and an optional audio file organizer. Playlists can have automatic selections based on your choice of dances and how often those dances should play, stops after some number of songs has been played, stops at a particular time, allowing of songs with certain keywords, sequences, and manual selection. Mix all of these in any order and modify them at any time.
Epris is a D-Bus service and command line client to listen to music. Unlike xmms2 or mpd, it uses GStreamer and D-Bus. It supports all formats supported by GStreamer, and can play both video and audio. It supports gap-less playback thanks to playbin2. It has an extensible command line interface, a small memory footprint, automatic deactivation, and an easy D-Bus interface for other UIs.
SvOlli's Little Audio Related Thingies, or SLART for short, is a compilation of rather simple programs that are related to audio files: it consists of a player (Partyman), a CD ripper, a tag editor, and some other tools. These programs can communicate with each other via a custom IPC bus, so a newly ripped track can be automatically queued in the player, for example.