If you like watching YouTube videos but prefer more control over how they are played, install this add-on in Firefox! You can download the videos as mp4's in up to 720p resolution with the standard version and then play them using a player of your choice. For a small, one time fee, you can download the videos at 1080p. I've tried several different add-ons and this one has provided the most consistent performance.

I did recently have a problem where the add-on quit working and after a couple of quick emails with the author, I was back up and running. A big thanks to Dishita for all the help!