PRGoogleBar adds a toolbar similar to the Google Toolbar in IE (as far as I've found, there is no official Google Toolbar for Firefox). It allows you to search Google (and other services such a Dictionary.com) directly from the bar. It also saves a history of your most recent searches.
Bookmark Backup- automatically backs up your bookmarks daily. Newer versions of Firefox have had some issues with the bookmarks being deleted. You can back them up manually, or you can get this.
