Considering that Win7 isn't finalized, nor are you using the recommended Win7 version on your netbook (i.e. Starter Edition)...I'm sorry to say this, but windows 7 certainly didn't reduce my netbook's power consumption, but instead made my battery life shorter. What does this mean? it means it consumes more power.
Many sites has done many tests to see if this "claim" was true. And after all, it wasn't true.
In order to consume less power, the OS itself will need to use less system resources. That's the keypoint.
I would agree that this could help reducing energy consumption, though many (business) users are probably turning it off anyway since they don't want the screen to go dark (i.e. during presentations) and are not concerned about running the computer idle.Windows 7 now manages hibernation and standby modes more reliably and efficiently, thus now users would likely be more inclined to use those features rather than leaving the computer on all the time.