Via Dave Donaldson's post, I came upon this post describing the Class Designer for VS 2005:

“But the real benefit is the real-time code synchronization. The Class Designer is in your project and is directly generated from your code. It is not generated from meta-data, but instead is generated from your VB or C# (or J#) code directly. This means that changes to the diagram are changes to your code. Changes to your code are changes to the diagram. The two are totally linked, because the source for the diagram is the code.“

I've always had to force myself to do class designs.  And honestly, I might as well draw them on the white board and erase them after I write the code rather than use Visio.  Why?  Well, the Visio code generation never worked right for me, and when it did work, my diagrams quickly became out-of-date. All these diagrams just ended up as “Source Safe Sludge” - You know, all that crap that ends up in VSS that you'll never use, but don't want to delete either.  Hopefully, this will be the answer for me. 

-B