Apophysis - Apophysis is a fractal flame editor and renderer for Microsoft Windows.
MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
Xaos - XaoS is an interactive fractal zoomer.
projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.
ChaosPro - Windows 95/98/NT fractal generation and exploration program with 3D, network, animation, 24 bit support, compatible to FractInt, compatible to UltraFractal.
Magic Music Visuals - Fully-customizable and highly responsive visuals for live and recorded audio & MIDI.