I have been debating on whether or not to share this. However-- like a gun, anything can be misused. It's up to the user. If you'd like to keep a youtube movie, or ANY movie you see online, then here goes. As you know, IE sucks. If you're a Mozilla user, sit back and enjoy this new trick. One button feature, downloads ANY movie you are viewing online. JUST the movie. Typically in FLV format.

Go to---- Tools- Options- Main- Manage Add-ons- Get add-ons. Select and install Video Download Helper.

Once installed, you will see a little rotating icon in your upper tool bar(3 balls- blue, red, and yellow). The rotating icon means your viewing a movie and ready to download it, permanently. Simply click on the tiny arrow next to the icon, and select either the bold print, or last video ID in the list. I've had a few mishaps, but mostly all great stuff, and perfect downloads.

https://addons.mozilla.org/en-US/firefox/

If you need an FLV format player, then go to Riva.
Riva VX: Riva FLV Player

In you need a converter, go to Any Video Converter.
Free Video Converter - Any Video Converter Free Version - convert video to any formats, avi to MPEG, avi to MP4, flv to MPG

ALL of these products are FREE, and I use them frequently(no viruses or glitches). You can even download, and convert to a cell phone friendly format. I've done it.