you can disable it totally or partially; methods described here
http://www.pcmech.com/article/firefox-3-...
or here
http://www.pctipsbox.com/how-to-disable-...
Install these two extensions (that's right, Two).
OldBar (This makes the awesomebar look like the old bar from FF2)
https://addons.mozilla.org/en-US/firefox...
and Hide unvisited
(Hide pages (bookmarks) that you haven't visited (since deleting or clearing history) from showing in the AwesomeBar)
https://addons.mozilla.org/en-US/firefox...