Audacious is a versatile music player for GNOME that has a low memory footprint and a clean GTK interface. It also comes with a Winamp-like interface that supports Winamp 2.x skins.
Audacious is a lightweight music player for Linux (but it seems version 2.5 will work on Windows too) that comes with two interfaces: a GTK interface and a Winamp 2.x-like interface that supports Winamp skins:
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 is a free, lightweight advanced audio player based on GTK2 which runs on Linux and many other *nix platforms and is focused on audio quality and supporting a wide range of audio codecs. Ubuntu 9.04 Jaunty Jackalope comes with Audacious 1.5.1 while version 2.1.0 is already available for download so if you really like Audacious, I bet you can't wait to upgrade.
Back in the day before I ran out of XP activations (stupid thing kept crashing), I used to LOVE Winamp for managing and playing my MP3 collection. It was just so quick, minimal and responsive compared to more management-based programs like iTunes. Imagine my delight when I switched to Linux and discovered XMMS. It was love until the honeymoon stage wore off, and became annoyed by the ugly GTK1 menus and fonts, and the lack of development.