Okay, the crappiest/strangest PC you have ever worked on. Keep the power above P166.

And that said, I say my own box is a bit odd.

AMD K6-2 500 (oc'd to 550)

I'm using an Adaptec SCSI card I got with what must be the LOUDEST drive on earth (2GB Seagate Barracuda)
2GB SCSI Seagate (Loudest drive on earth)
4GB IBM SCSI Drive ripped out of an Amiga (I think it was an Amiga - it didn't boot)

128MB PC100 SDRAM
SCSI Optical drive, speed unknown (Out of the same amiga)
Zip 100 SCSI drive (out of the same amiga)
IDE 56x CD-ROM
USB2.0 Card
Logitech Dual Optical Mouse
AT Mid-tower case (with ATX power supply)
An old IBM PS/1 Monitor (hits 800x600 - good enough for this)
Intel 10/100 NIC

And the box sits underneath my nightstand on its side, while the monitor is atop. Keyboard's in my lap, and the mouse (thank god for opticals) resides somewhere on my bed.