I am not interested in accessing the bookmarks menu or sidebar. The specific goal that I'm trying to accomplish is to be able to easily navigate (using only the keyboard) through the live bookmarks loaded from stack overflow by means of a feed reader and located on my bookmarks toolbar.
Notes:
I have found an add-on that supposedly does exactly what I need: Bookmark Keys, but unfortunately it doesn't work in firefox 3), and is not being currently maintained.
I'm using WinXP at work and Ubuntu 8.04 at home.
Edit: changed bookmark keys "not compatible" with firefox 3 to "not working" in firefox 3