When 8.10 Intrepid came out, I began the six month wait for 9.04 Jaunty. Of all of the new features, the best...by far...is the new notification system. Sure, it looks cool, but I had an actual use case the it would solve for me. When I download a file in Firefox, I have it automatically saved to the desktop and often switch workspaces (instead of minimizing my current collection of windows) to access the new file. However, when the file finishes downloading, Firefox uses its own notification system to alert me of that fact, and this notification system appears over top of the workspace switcher and is not click-through. One could argue the I should be using some key combination to swtich workspaces. This may be true, but it does not change the fact that the notification system in Firefox is wrong because it is not click-through and Ubuntu's notification system should be used instead anyway. Also, other users less technical than me might face the same use case as me but are not the type to memorize and use key combinations to accomplish their tasks.
Well, since Firefox is so amazing (because of its plugin framework), someone wrote this plugin to trigger the Ubuntu notification system whenever Firefox uses its own notification system. I learned about this plugin about a month ago, but (at the time) the compleation of a download also triggered Firefox's own notification. Then I read this blog post (that I found from Digg) that said that it was possible to turn off Firefox's notification system. I had previous assumed that this was possible, but I also thought that doing this would not allow the plugin to work either. Well, I was wrong, and it makes sense why I was wrong.
So, I was going to share the same informaiton that I read in that blog post about how to turn off Firefox's notification system, but while writting this blog post, I have discovered that the creators of that plugin must have also read it...because the plugin now shuts off Firefox's notifcation for you! So, in conclusion, just install the above plugin and you will have Ubuntu notifications (and only Ubuntu notifications) when Firefox finishes downloading a file.