Dell P4 2.26 ghz Optiplex gx270, 256 ram. Runnin' fine through 3 car now and stable a rock. Takes up a bit of real estate, but as you can see above, I've got the room!
Powered by a DSATX, and peripherals are listed in the post below.
Cut down, chopped up, welded (yup, I said welded) and mounted in many different ways over the years, it's still running strong. Taken alot of abuse at my hands, I'll keep it till it croaks!