In relation to the review on the Edison product I think its wise to point out that the free software is meant only as a guide to gently introdue to people the amount of energy a pc can waste annually.

If you are looking for cold hard stats on energy consumption of pc's Verdiem offer their commercial product Surveyor for this purpose. This software provide the actual energy savings based upon electricity rates and activity of the pc's (ie time spent in different power states) Research shows us that the vast majority of users will adjust OS power settings, some turn them off altogether. In a business environment with many thousands of pc's the financial sums that Surveyor can guarantee to save is considerable. In the workplace where productivity is also of importance it provides the features that allow it to remain almost invisible to the user. Edison is for the consumer as a gentle introduction/encouragement to be more aware of the energy a pc uses.

Matt Crane