That would be the Kindle, Amazon's wildly-overpriced portable electronic book reader. Its limitations have already been written about in many places. Given the $400 price, they will be lucky to sell over 25,000 of them before they run out of early adopters.
A glowing BusinessWeek article that calls the Kindle "the iPod of books". As Daring Fireball points out, that is waaay off the mark. There is a huge coolness difference between "I'm listening to my music while walking around" and "I'm reading a book on something the same size as a book that looks like it was designed by Dell engineers 15 years ago".