"Instead of buying whatever pre-built rack-mount servers Dell, Compaq, and IBM were selling at the time, Google opted to hand-build their server infrastructure themselves. The sagging motherboards and hard drives are literally propped in place on handmade plywood platforms. The power switches are crudely mounted in front, the network cables draped along each side. The poorly routed power connectors snake their way back to generic PC power supplies in the rear. (...)
Even today, Google is serious about exerting total control over the servers in their now-massive server farms. They build their own high-efficiency power supplies, and conduct fascinating, public research on disk failure. Current estimates put Google's server farm at around 450,000 machines - and they're still custom built, commodity-class x86 PCs, just like they were in 1999."
Jeff thinks it's a good idea to follow Google's model and to build your own PC, by using your favorite components. He even offers some suggestions.