That status bar was removed in Firefox 4.0. While some of the status bar items did find new homes, some did not, and you might not like where they ended up. There were also some nice innovations during the development of Firefox 4.0, such as progress/links/status in the location bar, which unfortunately didn't make it to the final release.
Status-4-Evar aims to bring back (some of) the old status bar items, give you more control over the built-in Firefox features, and provide new alternatives. More Info »
The extension provides "Status Text", "Progress Meter", and "Download Status" items. These toolbar items can be moved wherever you want by customizing the toolbars. Behavior of the toolbar items, and other additional settings, can be controlled in the extension preferences.
This extension can also act as a replacement for the Fission extension. There are preferences to show links, status, and progress in the location bar instead of the toolbar items.