UPDATE: I know just use del.icio.us ! http://del.icio.us/hendry I use several machines. I have put my .mozilla in subversion so I can check it out and commit changes on any of the machines I use. In plain english when I move between machines my bookmarks are the same. I found the following files to meet my needs:
bilbo:~$ rm -rf .mozilla/ bilbo:~$ svn update A .mozilla A .mozilla/default A .mozilla/default/ack41g03.slt A .mozilla/default/ack41g03.slt/70572827.s A .mozilla/default/ack41g03.slt/cookies.txt A .mozilla/default/ack41g03.slt/prefs.js A .mozilla/default/ack41g03.slt/70706990.w A .mozilla/default/ack41g03.slt/bookmarks.html A .mozilla/appreg
Most of the information about the files can be found here: http://www.mozilla.org/start/1.4/faq/profile.html#backup I find you need to also have the binary file .mozilla/appreg in there otherwise it asks to convert the profile and hence lose everything. It looks like it contains info about the bizarre SALT directory.