The server died earlier today (I had to drive home and reset it).
It's that same damn kernel panic I've been dealing with for a while. I thought it was the case overheating, so I replaced the case and power supply with spiffy stuff... that didn't fix it.
Then I replaced the video card... that didn't fix it.
I'm going to boot it with Ubuntu when I get home and run a memory test on it, so the server will be down for an hour or two while I do this. If I find a problem, I'll swap the memory out and hopefully we'll be good to go.