In one of the last Linux Magazine issues, there was an article with the title "Untangling the Web with Mozilla Weave". I really recognized the issue of having several Firefox instances with their own bookmarks/tabs/et cetera.
So I thought... let's give it a try, and so far... it works fine for me. I've now set up Weave on my Linux Laptop and Linux workstation at home. The upcoming week I will set up weave for my Linux workstation at work and on my Portable Apps Firefox on ahum Windows Vista workstation.