Where exactly are you reading that sales of current e-readers have "ground all but to a halt"? Is this your assumption because you think people are simply tossing aside the notion of an e-reader because the iPad will soon be released? If this is the case, you are dead wrong. For starters, the iPad is roughly twice the price of the Kindle/Nook. People looking for an e-reader (and only an e-reader) are not about to thrown down $500 (unless they want the other things that the iPad offers or have disposable income). Also you simply cannot overlook how different the iPad is vs e-ink. Like I said in my last post, we are comparing a backlit screen vs e-ink. Apples and oranges. It will be up to the consumer to decide which they prefer.
While I agree that the current Kindle hardware is rather ugly compared to the iPad, I do feel the Nook is still quite nice. By this fall I predict both the Kindle and Nook will unveil new devices that are fully touchscreen and color (with smoother refresh rates when changing pages). The iPad is not going to be the end of e-ink readers, it is instead joining the e-reader club.
@Yoppie: How long have you owned your Nook? Do you find the transitions between pages to be somewhat awkward? Are you worried that you will be tempted to purchase the next Kindle model, and therefore will lose out on your Nook purchases? Or would you simply wait for the next Nook model instead? (Like I said in an earlier paragraph, I see a fully touchscreen e-ink device with color coming towards the end of 2010).