Well, the HP iPaq 5555 was the winner. I bought it tonight and spent an hour setting it up, installing a couple more apps, getting activesync installed, putting a new picture on the back of the today page (a picture of Mary and me while christmas tree hunting) and just sort of playing. The thing looks great and feels great. Of course, I sat on my sofa, turned on the wireless and surfed the web a bit. Hurra! I'm very excited. Now, the organization starts!
As I get more used to it and set it up properly, I'm sure I'll be updating the blog fairly frequently with more details.
Many thanks to RoryB and ABC for their help.