I just saw the huge list of sites that yt-dl supports, and it's ... well staggering. I've been playing around with it a bit more, and I'm writing custom aliases for ease of downloading. For example I made:

alias bandcamp-dl="youtube-dl -x --audio-format mp3 --add-metadata -o '~/Music/%(artist)s/%(album)s/%(track_number)02d - %(track)s.%(ext)s'"

That alias allows me to do bandcamp-dl <http://some-album.url>, and then it creates the proper artist and album directories in my music library, adds the tracks as mp3s with formatted file names, and sets their metadata so my music app can pick it up.

Anyone else have some handy aliases or yt-dl commands that do something cool?