I'm another Palm alumnus.
I had four or five of them altogether, but I must have started reading on my first PalmPilot.
I can't remember what the first book was, though. I know I read some probably-illegal stuff like Zen and the Art of Motorcycle Maintenance
, some Baen Free Library stuff, and some out-of-copyright stuff, including Pride and Prejudice
, but I can't remember what was first.
It was very much an emergency backup, though. It wasn't until eInk that I was really happy to read from a screen.