I'm planning on getting an MBA when the new ones come out, but since the base 13" will presumably still have only 128 GB storage, I have a question about iTunes and music files. I have a large collection (maybe 150 GB) that currently all fits on my 2008 MacBook Pro, but it won't fit on the Air. Is there a way to configure an external hard drive (I have a MyBook 1 TB drive) so that whenever I plug the hard drive in, the music on the drive automatically appears in my iTunes and is playable? And then when I unplug the drive, the music files from the external drive would no longer appear? I don't need all of the music on the go, but I'd like an easy way to access it whenever I am at home.