As a cover musician, I use YouTube videos frequently to work on learning song licks and arrangements. It's incredibly helpful to be able to download audio files for use with AnyTunes so I can slow them down and isolate the parts I'm interested in to figure out those tougher passages. Easy Youtube Video Downloader does an excellent job of getting me the files without all the annoying adds, delays, time-outs, and pop-up redirects to porn sites that others have. They even let you decide how much the Pro service is worth to you, and you just pay that amount. It's well worth every penny, even if you donate the highest suggested amount.