Joel and I had a lot of fun doing this video for TechEd Online about the state of SharePoint reporting.
SharePoint Reporting—What's Up?
Key Points about SharePoint 2007 reporting.
If you want to roll your own reporting solution here are some things to keep in mind:
In summary, SharePoint 2007 out of the box reporting is big improvement over 2003. Portal and farm administrators may want more info and should look into third party solutions or rolling their own solution; however, when rolling your own be sure to do in a supportable way that doesn't impact farm performance.