For serious work? I find no difference between Win2000 and Windows XP or Windows 7 for that matter as to getting work done. Now maybe some of your programs actually specify a more modern Windows operating system, but I have not seen that (Win 2000 or later). After all, they try to insure that Windows programs need a particular operating system (for their benefit) but does it really? Most programs work just fine with older systems.
I can understand security as a precaution for using a more modern operating system, but really, unless your connected to the internet (with no firewalls or anti-virus programs), does it matter?
Most user programs require specific processor capabilities and ram, not the latest operating system. They just do not test on older systems...
I just don't have any compelling need to run on W2K, so any amount of overhead to make my stuff work on it is rather pointless. OTOH, having W2K around for temporary use is handy, typically it's in a VM and takes all of 5 minutes to gin up a new copy. And since W2K is all that runs on my old laptop, it does just fine for websurfing and such.
It's also worth noting that the first thing I do with a new XP or Win7 installation, is brain-damage the GUI back into basic/classic mode, so that it looks like the default W2K interface. It's still the best one out there, and I include OS-X, Linux, and any other versions of Windows in that assessment. W2K got a lot of things right.