Extreme base station puts the others to shame
Apple has created an attractive package, both in form and features. The Extreme looks like a warmer for a really expensive coffeemaker, whereas its competitors look about as cheerful as an Imperial Probe Droid or worse. Looks aside, it features a USB 2.0 port. Plug any USB hard drive or (nearly) any printer into the port (or plug in a USB hub and use 'em both), and they'll be wirelessly available to any Mac or PC on your network that's running Apple's AirPort client software - another strong vote for media sharing and network backups.