Earlier quoted context omitted.
though of course you can copy music off an ipod by copying the mp3 files off it like any other mounted disk, except that they are in a folder with its hidden attribute set.
And they're renamed with obscure filenames, and you can't do this with iPods touch or iPhones.
You don't have to use iTunes, or even an Apple app, to get things on and off an iDevice. For example: http://ecamm.com/mac/phoneview/
Blurb:
Multimedia Is No Longer Trapped on your iPhone, iPad or iPod Touch
Free your Photos and Movies -- Download camera photos and movies in just a few clicks. You can even use PhoneView to export the iPhone's synced Photo Library if you've lost the originals.
Music Made Easy -- Play any iPhone, iPad or iPod Touch music library through your Mac's speakers. Grab music, videos and podcasts from your device with one click.