The person who developed the Download Status Bar was obviously as annoyed with the pop up that Firefox throws when it downloads a file as I am. With this add-on, it will show a small status bar at the bottom of your browser that shows you the download speed and size of file downloaded so far. Hover over the bar and you can see even more information including download location, file save location, status and time left. And you can choose which fields you want to see in the customize section. That is easily found by going to Tools-Add-ons and under the extension box for the Download Manager there is an Options button. You can also stop, pause and resume downloads from the status bar.
I have done a little testing with it and it works as advertised. The number of options you can use to customize it is impressive. It is shareware, so if you choose to use it you can always slide the man a few bucks for the trouble he went through to make your life just a little better.