I started out in 1996 with a Pilot 1000 - unfortunately I don't have this anymore. Over the years I have collected a few PDA's/Pocket PC's/Handheld PC's/PDA Phones and the collection is still growing. Not in any particular order I have:
Palm III (a one off - it has a transparent case)
Newton Message Pad 100
Newton Message Pad 130
Everything I have is complete and working. Most are still in original boxes. There are some excellent websites around that have a history and pictures of PDA's and other really obscure devices like the Casio Zoomer. Check out:
I actually got to meet Jeff Hawkins a few years ago. Jeff invented the Casio Zoomer (at GRid) and then went onto invent the Pilot. He also started Handspring. A very interesting guy.