On several machines, I’ve got Seamonkey 2.0.2 installed. It has some very nice fine-grained preferences to control what shows up in the location bar.
I’ve also got a netbook where I put Firefox 3.6 because I didn’t need everything that’s in Seamonkey. Firefox has really limited preferences to control what shows up in the location bar.
Luckily, both browsers behave the same way using about:config. So it’s possible to get Seamonkey’s fine-grained control on Firefox, as long as you don’t care about a UI to do it.
A very useful article can be found here: http://kb.mozillazine.org/Browser.urlbar.default.behavior.
I read that article, and was about to calculate the value I wanted, when I realized the simplest way to do it is to go to the Seamonkey install, set up the preferences the way you want (“Autocomplete from your browsing history as you type”, “Match only websites you’ve typed previously”, “Only match locations, not website titles”, “Match anywhere but preferring word boundaries”, “Automatically prefill the best match”, “Show list of matching results”).
Then look at the values on Seamonkey for
browser.urlbar.default.behavior
using about:config, and enter that value (and any others you care about) in Firefox using about:config on that browser.
In my case, I set browser.urlbar.default.behavior to 49 to get what I wanted.