Recently I decided to try Windows Server 2008 on it. As usual the network card wouldn't work after the OS install. However, older drivers for the network card got installed. After running Server 2008 for a month, I had no problems with this machine running as a file server. Windows Vista SP1 uses the same kernel as Windows Server 2008.
"An update to the Windows kernel to bring the Vista kernel (version 6.0) up to date with the version in Windows Server 2008 (version 6.1)."
I figured that if the old driver worked in Windows Server 2008 it would work in Windows Vista SP1. I installed Vista SP1 on the machine today, and what do you know it worked. I had Windows XP drivers for the 3com card on a USB key, which got picked up without a problem. And not only that, Vista even picked up drivers for SBLive online (after complaining that the card was unsupported).
The machine is a 1Ghz, 512MB Ram system, and the system seems quite snappy. Ofcourse I don't have that many applications installed on it yet. Who knows how long Vista will last on the machine. Its a test system after all and Hardy is right around the corner! :)