I'm using a few things to improve bookmarks, i was using powermarks, but since its coming to the end of its life i thought id try and get it all back into ff itself. So
2 pane bookmarks, description says shows in sidebar in 2 pane style like opera, whatever it has 2 panes which is handy

(the home page is basically all in japanese, but it is easy to find at ff add ons site
Bookmark duplicate detector - as the name suggests
http://bookmarkdd.mozdev.org/Bookmark sorting
http://www.oregontec...rt.com/bookmarks.php is the home page, tho the version i have is later than the one mentioned on this page right now, so if ya want it i'd get it at add-ons site
OpenBook 1.3.4.1
Last updated: 2007.04.11
Allows for customization of the Add Bookmark dialog. The bookmarks tree can be automatically opened and elements can be hidden.
http://www.chuonthis.com/extensions/Ohh and I use Foxmarks to synchronize and store my bookmarks, makes them available anywhere as well as just the synching
These give me most of what i wanted, and it also means things like keywords and comments will be kept.