Great Spacesaver Rated 4 out of 5 stars
Omnibar is a key add-on that, along with others, helps me reduce all of Firefox's top-screen clutter to a single row.
I have two small suggestions.
1. I would like an option to reset to the default search engine after searching with a non-default one.
2. It would be nice to be able to wheel-scroll the search engines without having to hold Ctrl.