Visualization of Windows media player is really really amazing, and I often spent hours just looking at the video and listen to the music. Especially, I like "strawberryaid" and "illuminator" very much. It chould be even more cool if you choose "Randomization".
You can download more visualization from Microsoft’s website, http://www.microsoft.com/windows/windowsmedia/player/visualizations.aspx. With Windows Media Player 11 SDK that MS provides, you can even create your own visulaiztions, wonderful. http://msdn2.microsoft.com/en-gb/library/aa386694.aspx