While I'd be inclined to argue your statement that there's no justifiable difference between Win2k and Win2k3sufficient to justify migration, that's a whole 'nother story that I won't go into right now. It's your company, so it's your choice. The Windows 2000 exams are still alive and well and are likely to remain so until after the next Windows Server platform is introduced (the smart money puts this into 2006 or 2007, so the program still has plenty of life left; if history is any guide, Win2k3 sales won't surpass Win2k server sales until some time in 2005 anyway).
And yes, it is a wise decision to certify on what your company is using, because that's what you need most to know. If you get a Win2k MCSE, you'll be able to upgrade it later on simply by taking the 70-292 and 70-296 upgrade exams anyway.
This was first published in October 2003