The WD Live can use a hard drive, but it can also use a thumb drive or a network connection. It works pretty well for movies, so if you want to also route moveies throught your system then I recommend it. I don't think I'd use it just for music; the interface is not friendly enough. (It's clunky getting from one folder to the next. This is okay for a movie, becuase you do it once. But it I were selecting tunes it would quickly get old.)

Why not get a large iPod and hook it in directly?