For all the dollars and headlines that energy-saving CPUs garner, the hard drive is hardly a blip on the radar, but Hitachi claims to have the most efficient desktop drive yet in the Deskstar P7K500. The unit includes Hitachi's HiVERT technology for more efficient voltage conversion -- a method swiped from Hitachi's Travelstar laptop line -- and also features improved power management capabilities and "load / unload" tech to pull the heads off the drive for improved idle efficiency, with up to 44 percent power savings over traditional idle modes. Sizes range from 250GB to 500GB, and the drives should be available by the end of this year. No word on price.