Ordered a new kill-a-watt to check mine to see if it follows the predictions of power usage.   
I don't see figures for Memory, disk or SSD, motherboard, monitor,  fans....etc.  in projecting total system power usage.    
I have a M4A785 motherboard/amd phenom X2, two 7200jb hard drives, and an ATI HD5770 card.    I will compare real life to the numbers predicted by the websites.