2003 & 2007 Performance and Scalability - Capacity Planning

I hope you were able to attend Steve Tullis's Capacity Planning Session at the SharePoint Conference a few weeks ago.  If you weren't, which I'm sure most that read this won't, I'm including a great chart to help with planning on both 2003 and 2007.  Note the guidance numbers are based on beta 2.

My own commentary is don't put more than 500 site collections in a database.  Why? So you don't have to split it in the future.  In fact, if you know a site collection is going to be huge fast as in 5-50GB, why not put it in it's own database now? 

There are a number of new features which help the story of scaling libraries get a lot better.  Indexed columns for example.  The nav on the document center is great for nesting documents.  I haven't tried to push those numbers.  Story gets better, but you still have to be smart about how you mange it.