Don't forget the Microsoft Courier.
Courier is tempting, but two screens are going to make it uncompetitive for the market, and besides, dual screens are not really apt for a computer interface. As an ebook reader, yes, but I don’t think Microsoft is looking into Pixel Qi technology for it. Traditional LCDs are a reource drain, and two of them on a portable device is bloody battery murder.
Of all the ones I have seen so far, the most impressive by far has got to be the Courier. Here is hoping it lives up to expectations.