When I visited Sonos in June 2006, the folks there kept talking about how cool it was to use a network-attached storage (NAS) hard drive with the system. In most respects, an NAS drive is just like any other external hard drive, except that it's been set up specifically to run as a standalone drive without the need to keep a computer hooked up to it. In other words, once you put some song files on an NAS hard drive and disconnect your computer, the Sonos system can use those song files as if the NAS were just another source component.
Think of…