The integrated file downloader on Firefox is too bare bone. You can add some fancy buttons and tweak it’s file download behavior using the Download Manager Tweak addon for Firefox, or you can use the previously mentioned Download Statusbar addon to convert the download manager into a status bar. Another very useful addon is Download Scheduler.
Download Scheduler, as the name suggests, makes it possible to schedule downloads with Firefox download manager. This is useful for people who likes to download at night, or at any off-peak time to get faster speed.
Once installed the addon is simple to use. Right-click on any file you want to download and choose “Schedule Link As” rather than “Save Link As”. This will queue the download link to the scheduler which can be accessed from the Tools menu.
The time for the scheduled download can be set by going to Tools > Addons > Download Scheduler > Options.
For normal, prompt file download choose “Save link as” as usual.