This is a GAME CHANGER people. You can now download YouTube videos. Without the YT logo in the corner. There are a couple options, like idesktop.tv, and someone told me there's also a firefox plugin, BUT the one I now use regularly is keepvid.com

It operates off a very simple "cut and paste the url into this field and press Make Magic happen" principle, and there's no telling how long this will last for, but as of now I recommend downloading any video you've ever favorited.

Bonus info via onluker.com:

If you’re posting/linking direct to a YouTube URL, add &fmt=18 to the end of the URL and it’ll play in the HQ version .

To embed a High Quality Youtube video, you need to add the following code onto the end of both URLs in the embed code:
&ap=%2526fmt%3D18

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