Are you guys calculating your actual final rate (total bill / KwH used?) or the KwH rate on the bill? My final rate is 16.9 cents per KwH. The KwH rate can be misleading (at least in Chicago) as there are a stack of fees that you pay before you even draw 1 watt from the wall. Its in the neighborhood of 10-15 bucks. There are really creative names for each one.
One of the tests I have been wanting to do is to boot at a fixed voltage and see the power consumption difference at different frequencies under load. And then do the same but varying the voltage. Also pick up some samsung ram and see what kind of power consumption difference there is at 1.65 and 1.35 volts.