projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.
Plane9 - Plane9 is a revolutionary 3d visualizer where you never have to settle for just one view ever again.
MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
Amarok - The Amarok team is proud to announce the immediate availability of the result of 2 years of hard work, the beta release of Amarok 2. 9. This release is marked by improvements, corrections and polishing of nearly all Amarok features.
Quod Libet - A extensible Music player with Podcast support, web radio, playlists and many more.
Magic Music Visuals - Fully-customizable and highly responsive visuals for live and recorded audio & MIDI.