I have a Palm m125. It's discontinued, but they replaced it with the m130 (same, but with a color screen). Many of the PDAs on the market now have the mini-disks of some type. My brother has a Visor with one. I researched quite a bit before I replaced my m100 when it died (it had been a gift).
I love using my Palm to read. I actually paid for an eboook a couple years ago. I liked it; but decided that since it cost the same, and could neither be lent out or resold, it didn't pay. But with fic, with no cost associated, it means I can read a story anywhere! This is a very Good Thing.
Plus, I can read in bed with no light -- the screen has its own light.