XMMS

The X Multimedia System (XMMS) is a free software audio player very similar to Winamp, that runs on many Unix-like operating systems.
"XMMS is another player, and xmms2 is under developement. There is also Beep Media Player, which is a fork of XMMS."
Initial release: November 1997
Stable release: 1.2.11 — 16th November 2007
http://en.wikipedia.org/wiki/XMMS
http://en.wikipedia.org/wiki/XMMS2
http://www.xmms.org/

"Maybe I'm an idiot, but I still can't figure out why programs like Banshee, Rhythmbox, Amarok, Juk, et al, are considered to be so great. To me, they all seem slow and clunky and non-intuitive. (...) use XMMS or Beep and get a life."

Beep Media Player_
The Beep Media Player, a fork of XMMS code that uses GTK+ 2, started around 2003.
2005, October 22nd: Along with the announcement of the 0.9.7.1 release, the BMP development team also announced that BMP would not be actively developed anymore. Instead, the team would spend development effort on the next generation of BMP, called BMPx.
Last stable release: 0.9.7.1 — 22-10-2005
http://en.wikipedia.org/wiki/Beep_Media_Player

BMPx is the successor to the Beep Media Player. While the original BMP was a fork off XMMS, the new BMPx shares only a minimal amount of code with the original XMMS/BMP codebase, and was rewritten almost entirely from scratch. While early releases of BMPx retained the WinAmp look through a reimplemented skinning engine which made use of GTK+ widgets more extensively, the developers decided to shelve it in favor of a more integrated, iTunes-inspired look that popular players such as Amarok have adopted.
Latest release: 0.40.14 (07 April 2008)
http://en.wikipedia.org/wiki/BMPx
http://bmpx.backtrace.info/
"Don't forget BMPx, the development branch of BMP. SVN snapshots and screenshots are quite impressive."

Audacious is a fork of Beep Media Player 0.9.7.1, which is a fork of XMMS. William "nenolod" Pitcock decided to fork Beep Media Player after the original development team announced that they were stopping development, in order to create a next-generation version, BMPx.
Initial release: October 24, 2005
Latest release: 1.5.1 / 23 May 2008
http://en.wikipedia.org/wiki/Audacious_Media_Player
http://audacious-media-player.org/

Related:
Linux Media Players

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