I started with a grey scale Handspring Visor Deluxe, for $99 it was a refurb from Handspring. I figured if I hated the thing, I was only out $99 bucks.
Then I found PalmGear.Com and I love it. I have this thing not only as your usual scheduler/addressbook, but since I go out for appointments and wait a lot, having AvantGo cache websites (Wall Street Journal and others), I can stay up to date rather than read stale old issues of "People" in the waiting rooms.
I upgraded to a Visor Prism (65,000 colors) 2 weeks ago. Its just incredible.
Palma Sutra is a riot....the completely illustrated Karma Sutra, pictures and all.
Of course, my favorite, is while my Lancaster or Ar234 are climbing....Spy Hunter. Root Beer Tapper is great, too.
I haven't stepped up to the Pocket PCs or the big guns yet. These things upgrade/improve so fast, I'm kind of waiting to see what's coming next.
If you are wanting to program for your Palm/Pocket PC computer, there is a neat application to do so (does either or both). Check
http://www.appforge.com/