SHAREPOINT 2010 SITE COLLECTION SECURITY VIEWER UTILITY
This is a single application page that parses the entire site collection and returns the security layout on a single, drillable treeview interface. The page can be accessed either via a new option on the Site Actions dropdown, or as a new option in the Site Settings menu.
The page also lists off all Active Directory groups that have been given access to the site and enables the user to drill into them to see members of those groups.
LIMITATIONS: For performance purposes, I've left out parsing individual folders and files that have security inheritance broken. Also keep in mind that large sites with many subsites and libraries will cause the page to load longer, since all data is fetched on request.
NOTE: Any authenticated user that has access to the site collection can view this page, including Read-Only members.