My first one was a Sharp Zaurus:
http://en.wikipedia.org/wiki/Sharp_Zaurus
I read all of The Count of Monte Cristo on it. And came away with the realization that I will NEVER read a book again on such a small form-factor. I tried reading a book on my Sony XPeria X10 which does work fine but at the end of the day, the screen was so small (iPhone is smaller yet) that after being accustomed to E-ink and a CoolER/Nook, this was a prescription for pain.
Back in the day though the Z was a cool little device...I saved a company presentation to the Navy with it once because I could hack into a wifi network and then use it to do some last-minute coding on some files needed for a presentation to Navy officials...