Organize bookmarks does not show up in the bookmarks menu, and my individual bookmarks do not show up in show all bookmarks. Only the folders and the bookmarks inside the folders show up.
I have Firefox v5.0.1 running on Lion.
"Bookmarks > Organize Bookmarks" has been renamed to "Show All Bookmarks" in Firefox 4 and later.
A possible cause is a problem with the file places.sqlite that stores the bookmarks and the history.