A word about using the built in Navigation Manager...
If you use it as built in vB 4.2.0, add navtabs, menus or links and then delete them, the phrases used by those items are left behind in the phrase table.
Evidently it was designed to leave unused data in the database...
http://tracker.vbulletin.com/browse/VBIV-15177
Unfortunately, for some reason I don't have the option to petition to reopen that bug.