Plastic Logic is more than a year away (see
http://www.plasticlogic.com/FAQ.html). And no one really knows what is comming from there...
Is wifi really important for you? You do understand that the current e-ink tecnologie does not allow you to use the device as an netbook, or something similar?
So I agree with the others: If you want an e-book reader now, buy one NOW. There will always be something better and nicer a few months latter...
If you want to buy one now, you should consider the Cybook Gen 3 (I have one and it works great - but it is only a e-reader!). If you prefer to wait a while, you could consider the txtr...