Power saving modes WinXP

I'm borrowing the Watts Up? PRO from a friend at work so I figured I'd test out all the various options that WinXP gives for saving power. I have a WinXP Pro box with 3 internal hard drives, a DVD-ROM drive and a decent video card. Here are my results:

Computer off: 3.7W
Computer booting: 120-160W
At the login screen idle: 115W
Logged in to an account idle: 115-160W
Turn off Hard Drives (XP Power saving mode): 107W
Standby mode: 66W
Hibernate mode: 3.7W

The turn off hard drives mode really didn't save as much power as I would have expected.