fit-PC Slim is said to be the “smallest, most energy efficient PC available,” and at 13 ounces it arguably could be. The fit-PC slim is housed in a 330cc enclosure (4.3 x 3.9 x 1.2 inches), uses a measly 6 watts of power, and runs on a 500MHz AMD Geode. This machine is available in a 256MB configuration for $220; a 512MB WiFi version (with no hard drive) for $245; or a 512MB / WiFi / 60GB hard disk version pre-installed with either Ubuntu or Windows XP Home SP3, for $295 or $335.

Product page