I still think it is a stupid decision that Microsoft did not bring out Windows 2000 SP5. Now here is their "shut-up or migrate to win2k3-pack" for Windows 2000; and look at the name Update Rollup Number 1 , suggesting that their will be more in the future, I highly doubt that, while officially Microsoft supports Windows 2000 to 2010, regular support ends this Friday.
The Update Rollup contains all security updates produced for Windows 2000 between the time SP4 was released and April 30, 2005, the time when the contents of the Update Rollup were locked down for final testing by Microsoft and by external beta & customer sites. The Update Rollup also contains a number of updates that increase system security, reliability, reduce support costs, and support the current generation of PC hardware.
We encourage Windows 2000 SP4 customers to install this update. For more information about this release and to download the update, see Microsoft Knowledge Base Article 891861
http://support.microsoft.com/kb/891861