If you can't eliminate Amazon or Sony, go for the little cousin. If that comes through, bye-bye Nook.
Actually I see it as a win-win. I think they can use the BILLIONS that Apple can bring to the table, and the added weight of someone invested in e-books having a dead tree division will make it easier for Amazon/Apple-B&N to put the publishers in line.
Because honestly some of the publishers are stuck about 90 years in the past. They don't want to change the model, even when it could make them money because they are used to being the big boys on the block.
To be truthful though.. I didn't think the Nook was too much. The Nook Color was an interesting widget but (in my opinion) it was a step back from the ebook reader designs. I wouldn't rub out the Nook quite yet though, it has a SIMILAR but not the same role as the iPad. It does well enough to justify keeping it around the market. of course the book store/iBooks might change a bit in the process though.