The first ebook I ever read was Bruce Sterling’s Hacker Crackdown on my Newton Message Pad 2000. It had a big and bright screen — “the best screen for reading eBooks on the (non-)market” says DJ Vollkasko — but it could get a bit little heavy at times.
Crackdown is available for free, along with perhaps 16,000 others, at Matthew McClintock’s ManyBooks.net. Downloads are available in 11 different formats, or you can read online.