Audacious is a powerful audio player for Linux which resembles the older XMMS, only using GTK2 toolkit for its interface. It supports XMMS and implicitly Winamp 2.x skins, coming with support for various audio formats, including MP3, Ogg Vorbis, FLAC (Free Lossless Audio Codec) or WMA (Windows Media Audio).
Audacious was forked from Beep Media Player, which was also based on XMMS but development was discontinued in 2006. Audacious is currently maintained and the latest version was released in July this year. For a tutorial on installing the latest release in Ubuntu 9.04, check out this tutorial I've put up a while ago.
The version I used for this review is 2.1 as it comes included currently in the Ubuntu 9.10 Karmic repositories. Audacious comes with the typical, simple interface some of you are used from XMMS. It includes a main window with regular play/pause/stop and volume buttons, a 10-band equalizer and the playlist itself.