Bookmarks' Full Titles version 2.0 is a tiny extension for Firefox 2 that eliminates truncation of bookmarks' titles, in the Bookmarks menu and in dropdown menus from the Bookmarks Toolbar.
Bookmarks in top level menus - i.e. directly under the Bookmarks menu or directly under a folder on the Bookmarks Toolbar - don't expand to full width, because submenus would be inaccessible if they did. But this extension does make them somewhat wider than they are usually.
It was inspired by some code _Jim_ posted to MozillaZine Forums that I then packaged into an extension for ease of use and general good karma. Besides, it took about thirty seconds to hack up based on Back/Forward Dropdown Remover.