I recently updated from 2K to 2003 - a vast improvement. You will have to decide for yourself on licensing, but I got 10 copies of Office2003Pro on ebay for ~$600.
Having to reboot to get Outlook 2000 to properly restart was a regular thing for us - 2003 seems to be much better. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~