Musical Instruments
YouTube's videos attract plenty of eyeballs, but your ears likely get plenty of enjoyment out of its contents, too. And if you'd like to turn those videos into audio files and save them, MP3 Rocket (free) makes it about as easy as it could be.
The internet has made it easy to download just about any song you want for free, but frankly, illegally downloading music just isn't an option if you're the honest type looking to support the artists and producers who enrich our lives.