Compaq Proliant with a 250 Watt PSU:
550 MHz PIII
~300 MB RAM
1x Maxtor 4 GB
2x Seagate Barracuda 80 GB
1x HP CD-RW
1x S3 video
2x Ethernet (3COM + Intel)
1x ISA SoundBlaster

The PSU weight is about the same as a contemporary Enermax for 350 Watt.

All right, count me in. Let's see what I can get out of my machines until they burn down

Indeed, barracuda is much, much quieter. However, you should try to suspend your WD first. I had a good experience with that. I simply hanged my WD by a couple of strings in the 5 inch bay. It is not as quiet as barracuda but really gets rid of almost all the whine.