Aneesh, if you install the wundrbar toolbar for firefox you can actually replace the location bar with wundrbar! It's a big leap, but it's there as an option. Or you can just use the toolbar, which automatically positions itself below the location bar.

Right click on the wundrbar search box and select 'add a keyword for this search'. Then you can just type 'keyword' <blah> in the firefox address bar.

Edit: This doesn't work with wundrbar for some reason.