Turns out I've been able to forestall the inevitable for a couple more years, at least.

I'd checked with Symantec, McAfee, CA, Panda, Kaspersky, Avast, F-prot and Eset, and none of these companies could offer a Windows Server anti-virus client at a reasonable price.  All of them demanded that you purchase a 5-10 user license pack for $250-500+ per year.

No. freaking. way.

But I'd forgotten about AVG.  Most people only think of AVG because of their free anti-virus (which doesn't run under 2000 Server).  But they do offer a 2-user business license for only $83 for 2 years.  Now TWO licenses I could actually use, I'll just give one to my SO.  He had been running the free version of AVG, but the pay version has a few extra features (and I paid the extra $20 to get 2 users/2 years of anti-spyware as well).  That comes out to just $25 per user per year for anti-virus and anti-spyware.  Not bad at all.

And I can keep running Windows 2000 until Microsoft finally stops providing security patches.