MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
cmd.fm UI - Music visualized and controlled via a command line interface
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.
Graphic Foundry - High-impact audio reactive music visualizers 💎
projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.
SYQEL - Bring your music to life