I have a Nook but I don't really use it that much and still buy lots of printed books. I don't know how to explain it, but every physical book has a sort of personality (size, color, font) that goes with it and with the nook all books are the same. I only ever buy books online if they are hard to obtain or are digital only.
Ebooks are also very expensive, often as expensive as a phyisical copy and until the publishers start to bundle every printed book with it's digital copy I don't see myself spending more money on them.