One of my favorite web parts in SharePoint 2010 is the Table of Contents Web Part. I used it on nearly every project to create a security trimmed listing of sub sites (like on a projects web).
While working with a client, I noticed that only the first 20 sites were being listed and could not figure out why. After doing some digging, I found that it uses the same counter that is used in the: Site Actions| Look and Feel | Navigation | Maximum number of dynamic items to show this level of navigation.
The default is 20. I am not using dynamic navigation on this particular web so I up'ed the count to 100. I saved the settings, refreshed the page and all 41 of the project sites appeared in the list.
Happy SharePoint'ing!
E.