Latest nightly build of Firefox 3 sports the much improved location bar autocomplete, that unlike Firefox 2 which only looked for web addresses in my history, this one looks on visited and bookmarked page titles and tags along with web addresses.
The autocomplete list now shows page titles and addresses in two different lines and colors. The top line has the website’s icon, title name and a star (if the site is bookmarked by you). The second line is much smaller and has the URL of the website. As you type the matching portions of the title and URL are highlighted and underlined so that you can easily tell what matches.
Personally, I really liked the multi-line approach to the Location Bar, and if I am not mistaken it is the first browser to have this (maybe Opera has it).