Music library spanning multiple disks.<p>This is my #1 desired killer feature, and no one has done it right (or even attempted it.)<p>I have 100s of gigs of music, but my MacBook Air can only store a portion of it. I want to connect the external drive and have the player see it all without changing the library pointer. I also want to be able to select which songs to mirror onto my laptop - a &quot;checkout&quot; feature.