My add-on https://addons.mozilla.org/en-US/firefox/addon/categorize/ combines bookmarks and tab-management. It lets the user group bookmarks into sets that a user can open all at once or singly. This approach almost completely eliminates the need for an address bar.

Another interesting feature of the add-on is that it unifies bookmarks and web-search. The two seem totally disparate but they can be integrated seamlessly in a very cool way. Check http://techuser.net/beyond-chrome.html for an overview of the approach.