Voltage Frugal PCs?

Red Rocket asks: "There's no shortage of information on building special-purpose PCs. Water-cooled PCs, refrigerated PCs, overclocked monsters, quiet PCs, tiny PCs... it's all there. But there seems to be little info about building a PC that sips the minimum juice from the power grid. So I'd like to throw it out to the Slashdot throng to see what you've done." It would seem like a PC with a low power consumption would be an interesting selling point, especially for those people who are more concerned with something other than high clock speeds. Is there someone marketing a low-powered PC solution (CPU and monitor), if not how difficult and at what expense would it cost to build one?

"I'm going to leave this thing on 24x7 using electricity that I'm paying for so power consumption becomes a real issue. Which CPUs, chipsets, memory technology, and hard drives provide the thinnest power profile for an always-on machine? I'll be running NetWare because it provides the stability of Linux/BSD, exceeds the configuration ease of Windows, and provides the security and worm/virus immunity of...well, NetWare. That'll let me set up that yummy iFolder [novell.com] and have constant access to my data from anywhere on the Net. It also means I'll probably need to stick to an AMD or Intel CPU since AFAIK the Transmeta and Cyrix/VIA chips, like most IS managers, don't really get NetWare. CPU speed isn't much of an issue. 633 MHz should be plenty. Am I the only miser setting up a server?"