OCIA.net takes a look at the Western Digital 320GB USB/FireWire My Book in their latest review

Right away it's clear to see where the name of the product comes from - it looks like a book! The front of the My Book has two clear rings. The inner ring is lit with a blue LED to show the remaining free space on the drive. The outer ring also has a blue LED and acts as an activity light, flashing when data is copied to or from the My Book. A button lies in the center of the inner ring and is used to turn the drive on/off. Each side of the My Book has a Western Digital logo in the center.

Western Digital 320GB USB/FireWire My Book Review