Don't be deceived by this Firefox extension's unassuming user interface, it's actually a very capable video player.
NetVideoHunter operates via a tiny icon and counter that appear in your status bar. When you click on the icon, a window appears for viewing videos. A step-by-step guide walks you through the process--a definite plus for novices. Watching a YouTube video, for example, adds it to the counter. From there, click on NetVideoHunter's tiny icon to reveal a video link. We had two choices: to play or download the video. Play starts the video, while download saves the FLV to your hard drive.
Watch out for where you save the video, and be wary of a help link on how to play FLV files that did all of nothing. Those are minor problems, though, and NetVideoHunter works great. The videos quickly appear in the queue, and play/save worked without any issues. This app is recommended.