** For full disclosure, I'm a group program manager on the SQL Server Manageability Team.
In my 15+ years of experience in IT and software development I’ve never found the Holy Grail answer to “should I upgrade to the next version of not?” It doesn’t matter what software is the context of the question, the answer always comes down to what your needs are and does the new version satisfy those needs. For people running SQL2K they may need mainstream support which becomes their motivation for upgrading.
For a side-by-side comparison of features by edition in SQL2K8 see this Books Online page:
I think you’ll find that SQL2K8 has a bunch of value in every edition. And don’t forget that Express and Express Advanced are free. Yes, they have restrictions on memory and CPU usage and database size but why shouldn’t they? Microsoft is a for profit company, they can’t give away all of their software.
A few of my favorite Database Engine features in SQL2K8 are Policy-Based Management (available in all Editions – although it has limited functionality on Express), Data Collector (available in all but Express and Express Advanced), PowerShell integration (available in all Editions) and the Auditing Framework (available in all Editions). BTW: this article incorrectly stated that Policy-Based Management is only available in Enterprise Edition.
Take stock of your current situation, learn about the new release (from a reliable source) and reach your own conclusion if upgrading makes sense for you.