+1Energy efficiency only matters depending on the usage scenario:
Energy Efficiency matters in: laptops and smaller mobile devices where battery capacity is very limited, servers, rendering farms, or other cases where one or multiple machines are running near 100% 24/7, or in a developing or underdeveloped country where electricity is still relatively expensive.
Energy Efficiency does not matter in: the one or two household desktops for daily use and/or gaming. In fact, in these cases performance should be the ONLY metric (provided sufficient cooling is utilized). I would MUCH RATHER pay $10 per year (actually it'll be less), for faster I/O, faster processing time, better graphics, and for the occasional bursts of rendering or calculations to run faster, then to run at some 'energy cost optimum' and sit around sipping coffee.