Well I don't build from my own computer, but these are the specs for the computer I am building from.
Intel Core2Quad 9550 (as fast as an older Core I7, currently not overclocked)
Asus P5Q Pro Turbo
8gb of Gskill DDR2 ram
1Tb Western Digital Caviar Black (one of the fastest conventional drives)
Nvidia something or other graphics (it's a server, who cares)
Ubuntu 10.4 LTS 64bit
32meg Internet connection (up to)
Headless (no monitor)
Hosting location, dead center of the US.
Yes it as fast in ghz. But it doesn't have the Intel interconnect thingy, or hyper threading which helps a lot when building android!