At the risk of stepping out of my area of influence and into an area of concern I will give you my wife's thoughts on the subject of PDA's. She is a PDA fanatic, an intergrated technology expert, and has a whole host of PDA's. I think that her thoughts will be of some value to you. Here is what she wrote to a gentlemean that had asked something similiar to you as to what a PDA can do for him and what to look for.
"Palm OS versus Windows Mobile (WM). Palm greatest asset is that their devices are simple to use. There’s hardly any learning curve. Inputting letters is done in three ways, virtual keyboard, graffiti (like short hand, but really easy to learn), and via keyboard accessory. Palm also has many applications available for sale and for free. WM is not so easy to learn. It isn’t like regular windows and the OS is not as stable. One real plus is that WM from Dell gives you two slots (CF and SD) and it also has built in Bluetooth and WiFi. Applications for it are available, but not as many as the Palm OS. I have both, but I use my Palm much more.
You need to know what you want to do with it. If you want continuous wireless you may want to consider a Palm Treo 650. That way you have the phone, Internet, and a small built in thumb board. I have never used one. I don’t like combination devices, plus you are paying for Wifi access. This is what I use my PDA for: reading novels, calculator, notes, work on documents, read adobe files, watch movies, keep pictures of my kids (digital photo wallet), track expenses, play games, email, light web browsing as well as keep addresses and appointments. I have the Palm T5 and TX. The T5 is faster and has more storage, but the TX has built in Bluetooth and WiFi. While you can get a WiFi card for the T5, it is not as convenient since you only have one SD slot. When wireless you have to remove you SD card and insert the WiFi card. If you are at a hot spot you can simply log onto the net for free. Both have a nice big screen.
I think that before you buy you should read the websites that have reviews, user forums, and blogs (just google it) as well as the Palm site and Dell’s. There are other makers of WM devices, but I have never used them and they are quite expensive. Basically for you first PDA, I would suggest the TX. It’s only $300 and then you could decide if this tech is for you. Also see them in person at Bestbuy or other store. Hold it, play with it. I think you will like it. If you do get one, buy a nice case for it." end of message
This gives you an idea of what a PDA can do for you. It is an organizer on steroids. My wife carries hers wherever she goes. She is never late for an appointment unless she does not input information into her PDA.