MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
Kauna - Kauna is a music visualizer. Kauna renders any sound reproduction in system.
VJmachine - Music Visualizer - Make a VJ show like a PRO. Music visualizer for a unique tight symbiosis of sound and video.
Morphyre - Animated, 3D Music Visualization with thousands of unique scenes.
Magic Music Visuals - Fully-customizable and highly responsive visuals for live and recorded audio & MIDI.
Plane9 - Plane9 is a revolutionary 3d visualizer where you never have to settle for just one view ever again.