SQL Server Magazine has done some wonderful work in developing a new system view map for SQL Server 2005.  A hard-copy of the map was included in a recent mailing of the magazine.  But what's a person to do if they don't have a subscription?  First, get a subscription!  (grin)  Second, check out this resource:

http://www.microsoft.com/downloads/details.aspx?familyid=2ec9e842-40be-4321-9b56-92fd3860fb32&displaylang=en

If you've been with SQL Server for a while, like I have, you can recognize at a glance the evolution and growth of SQL Server as a product simply from its metadata maps.  The earliest maps were quick and simple.  They could be grasped almost instantly and it realistically didn't take a lot of work to lay them out.  I can remember doing it myself using ER/Win and PowerDesigner back in the 1990's. 

But as you look at the system object map and relationships between those objects for SQL Server 2005, it doesn't take a rocket scientist to tell you that this is a complex and Byzantine set of objects and relationships.  It'll be hard to keep all of this valuable information in your head.  So I strongly encourage you to download it (or obtain it from SQLMag) and hang it on your wall.  You'll be glad you did!

Cheers,

-Kevin