Download Statusbar offers several ways to view the status of your downloads using Firefox without the annoyance of a separate dialog box. I've chosen to use the mode where it's just another icon on the status bar. You can opt to have an additional bar added above the status bar when downloading.
After your file has downloaded, through a simple hover, you can see all the specifics about the downloaded file(s). For example, you can see the site you downloaded it from, the file size, and the time it took to download. Additional options include a notification when complete and even an auto-virus scan.
I like it just because it reduces the clutter.