Step 1, install greasemonkey: https://addons.mozilla.org/en-US/firefox/addon/748
Step 2, install this greasemonkey script, just detaches the suggestion box from the HTML, making it disappear, the more elegant solution would be if facebook would just not send the HTML in the first place.. but that's asking too much mehtinks: http://slicer.ca/files/facebook_desuckify.user.js
Step 3, enjoy facebook without the stupid suggestion box.