I have just uploaded a new application that extends IIS Manager 7 for Windows Vista and Windows Longhorn Server that adds a new Reports option that gives you a few reports of the server and site activity. Its features include:
Click Here to go to the Download Page
I'm working on a second version that will allow you to create your own queries and configure more options like Chart settings, and ore.
If you have any suggestions on reports that would be useful feel free to add them as comment to the post.