A couple bucks cheaper than another one sure to go popular soon (at $15 + shipping), plus a chance for 4% BCB from Buy.com. Made by Targus, so it should be excellent quality.
The ASUS backpack by Targus features a padded notebook section designed to specifically protect your notebooks. It is ergonomically designed to make carrying heavy books and materials easier, putting less strain on your shoulder. The durable molded carry handle makes it easy to transport the case around campus or to and from meetings.