Minimalism - Nice, simple, and relaxing. You can stare at it for hours.

Minimalism (this visualization plug-in)is part of the Developers Gallery Visualization Toolkit. Using this toolkit and the accompanying tutorial you can make new OpenGL based visualization plug-ins for Winamp in a single step. All the technicalities are hidden from you in an object file and the only thing you are required to code, is the render function of the plug-in!

The visual itself is decent... the center sphere with planetary rings looks cool... definitely minimal and not exactly mind blowing. The visualzation toolkit option, however, allows users to create new openGL plug-ins for Winamp.