I should explain I've got the Pentadactyl addon installed, and ideally I would then turn all those bars off, anyway. You do : o (think vim commands) to open a URL, but if what is typed cannot be resolved into one, it is sent to the default search engine ... in this case, still Google!

I have also tried changing some other settings in about:config:
browser.search.defaultenginename
browser.search.order.1
No luck! Does anyone have any ideas?