Dell Studio Hybrid - Only uses 44 Watts of power

Dell Studio Hybrid - Green PC and Compact
Intel® Core™ 2 Duo T5750 (2.00GHz/667Mhz FSB/2MB cache)
Genuine Windows Vista® Ultimate SP 1
2GB Shared Dual Channel DDR2 at 667MHz
160GB SATA Hard Drive (5400RPM)
Slot Load CD / DVD Burner (Dual Layer DVD+/-RW Drive)
Dell 7 in 1 Media Card Reader
Intel® Integrated Graphics Media Accelerator X3100
Integrated Stereo Audio with 5.1ch digital output (S/P DIF)
Dell USB Multimedia Keyboard & Optical Mouse
Integrated 10/100/1000 Ethernet
1Yr Limited Warranty with 1Yr Next Business Day Onsite Service with Complete Care and 1Yr Tech Support

Size and materials
Our smallest design is about 80% smaller than standard desktops, and it contains about 75% less printed documentation by weight when compared to typical tower desktops.
Power usage
Uses about 70% less power than a typical desktop, and meets Energy Star® 4.0 standards with an 87% efficient power supply.
Packaging
Studio Hybrid packaging is made from 95% recyclable materials. And the Studio Hybrid comes with a system-recycling kit, so you can help preserve and protect the environment.