I am loving the YouTube grabber for Mac. As the name implies, you can use it to grab YouTube videos and download it on your computer. It gets download as an FLV file, but you can use the same software to convert the file to MOV or MP4.
I am also loving the iextractmp3 which I use to convert FLV files to MP3. Very useful, for, say, when you can’t find an MP3 file of that Bagets theme song but there is a video of it on YouTube. It’s so quick and easy to use too.
Oops, gotta get back to my iMovie project.