Kauna - Kauna is a music visualizer. Kauna renders any sound reproduction in system.
MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
Morphyre - Animated, 3D Music Visualization with thousands of unique scenes.
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.
Plane9 - Plane9 is a revolutionary 3d visualizer where you never have to settle for just one view ever again.
projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.