iTube (no, not the Fatman dock) by Aquallusion is an iPod speaker that lets the user see the music come to life in flowing colors and bubbling effects.
The sound is spread in 360° angle from the bottom of the 30-inch tall speaker, and the light effects can be altered using the remote control.
Here’s a video demonstration of the iTube speaker in action:
The list price for the Aquallusion iTube is set to $249. (Update: Link removed because the website no longer exists.)