First off, thanks to John Carroll for answering my recent call for help so quickly! John sent me a link to a very cool app that helps to mitigate the ever-present nuisance of application window clutter. It's called MinimizeToTray.
MinimizeToTray is a Windows-only program that allows you to minimize all of your open Firefox and Thunderbird windows to your system tray - the area of your taskbar to the right, near the clock. This is pretty useful, as you know how crowded your taskbar can get when you're working at full speed.
Also, this app can speed up some common tasks for you by allowing you to execute some commands by right-clicking on the tray icon. For example, if you have Thunderbird minimized to your system tray, you can right-click on its icon and select "Compose New Message" to start writing a new message.
This seems like a pretty nice app. Hope you find it useful!