To my knowledge, there are companies which still works on SQL Server 7.0 and SQL Server 2000. But in the last quarter of 2005, Microsoft released SQL Server 2005. Though I have been using that product personally since that time and officially for more than one year now. I am not too sure whether everybody has migrated to SQL Server 2005!
That being a case SQL Server 2008 (code named: Katmai) is around the corner now :) Hmm we need to wait and see how many of them migrate immediately.