Well it embarrasses me to admit this but if by ultimate one means what first induced me to bu my first e-reader (Sony PRS 505) it was because a friend had and e-reader (different manufacturer and not even e-ink) and I thought it was so cool that I just had to have one. What kept me using it and led me to upgrade to the Sony 900, and now also a Nook Color, is that it is such a great platform for obtaining, storing, and reading books.