My first handheld device was the Apple Newton Message Pad. I really loved this handheld; the size was larger than today's handhelds which made reading and writing on the screen very easy (although it was a bit large to fit in my pocket).
A change in jobs moved me away from the Apple/Macintosh environment and support for the Newton on PC's was non-existent. So, I picked up an IBM WorkPad (running the Palm OS).
The WorkPad did a very nice job for me, especially with the synchronization between it and Lotus Notes, my desktop software of choice (I have been a Lotus Notes Application Developer for about 10 years now).
After having my IBM WorkPad crushed under the tire of my Nissan X-Terra, I purchased a Handspring Visor. I liked the Visor because it was compatible with software I had been using with the WorkPad and had the potential to expand with the Springboard slot in the back.
After seeing the color screen with the prism, I upgraded to the Handspring Visor Prism. The Prism displays 65,000 colors. And, with the Springboard expansion slot, you can always snap in a variety of optional Springboard modules. The Prism's internal lithium ion battery is rechargeable.
I used the Handspring for years, then finally upgraded to the Palm Treo 650. The Treo was primarily a telephone with a Palm built-in. It was a slick device that served my needs very well.
The Treo was my device of choice until I walked into the Apple store one day and found the iPhone on display. The phone had just been released and was in pretty high demand, but they had several on display. I spent about 30 minutes playing with one and decided that it was the phone that I wanted. They did not have any 8GB versions available at that store, but they had 4GB models - I'm not much for listening to music on my phone, so I figured the 4GB version would be enough for me.