[zunzun]

doxygen turned the classes into hyperlinked web pages for a ginormous complex enterprise code base we worked on, it made understanding the code structure and class organization trivially easy - and we could email code structure links to each other for collaboration! For this purpose I rate doxygen as at least 11 or 12 out of a possible maximum of 10.

[c3c]

Does it create call diagrams by any chance?

[zunzun]

All method references are hyperlinked, so that you can click through and trace calls.