Corsair today managed to achieve 80 Plus certification on every power supply in its range. This means when operating at 20%, 50% or 100% load, the power supplies are at least 80% efficient in their conversion of energy. This is great for them, especially as the main struggle is with 80+ efficiency at lower loads. Anyhoo, I was thinking of the best product.

Hybrid PSU/Heater unit. See, energy conversion efficiency is input energy divided by desired/useful output energy. PSUs are inefficient because they produce heat. But! What if you wanted the heat! You could have a 100% efficient product. Epic win. 100% efficient to please the eco bunnies. These eco bunnies also lap up anything with 'hybrid' in it, so I reckon I'm onto a winner of a product here.