Wow, will be printing this out for future reference, thanks!
I got them back. Day before yesterday I had d/l'd an addon called "Foxmarks" that syncs your bookmarks on all the computers you use, and I think that may have been what screwed it up. It also gave instructions for recovery, though.
WHEW! Dodged that bullet -- I *never* would have remembered that whole, subdivided list! I suppose this is also a gentle reminder to do backups.
Candy