I was in Barnes & Noble the other day and was visually accosted by a huge Nook display just inside the door. I had never had an eBook in my hands, so I walked over out of curiosity.
DISCLAIMER: I don't own an eBook nor an iPad, so this opinion is based on some out-of-curiosity online research plus about 5 minutes with an iPad and a Nook. One of my students has a kindle, and I've looked at that as well.
One of things things that struck me about the iPad was the glare from the lights overhead. Although I admire the ipad's funcionality and the elegance of the design, the glare factor on the screen makes it much less useful for reading. The frustration factor would have been exceedingly high trying to read a book on an iPad, especially in sunlight.
The Nook was a welcome contrast in this department [pun intended, of course!]. It's matte screen, although smaller in size, was much more pleasant to use in a variety of lighting situations. I was fairly impressed - plus the fact that it accepts SD cards for additional memory, has software so you can access your purchases on a variety of platforms (Macs, Windows, iPhones, Android.....), and the battery is USER-REPLACEABLE makes this reader very attractive.
According to B&N the number of titles available for the Nook is greater than for the Kindle or the iPhone by a significant factor. Granted, I have no way to check that out, but given that B&N has moved heavily into the education market (i.e. TEXTBOOKS) it's probably true.
You can also "lend" a title to another Nook user, which is pretty cool - and one model is equipped with both 802.11 [wireless] and 3g [cell phone] radios.
They come out with a color version November 19, 2010. That's one tech item the MaconMacGuy is anxious to check it out.