Well, I've been using a Palm OS device for about 3 years now, so I might be able to make some suggestions. Most PDA's out there can put a word or text file on them, but if you are looking to spend under $200 then you are probably going to have to go with Palm OS, not a Pocket PC.
If you are going to want to put a lot of documents on your Palm, you will probably want to look for a device that has an expansion slot. Most of the newest Palm devices, as well as the Sony Clie Handhelds, have one that you can store your documents on. I have a Palm M515 with a 64MB SD card, and I have about 30 MB of documents and books on it. It takes a minute to read the card to find all of them, but I find it really convenient.
I use the address book, datebook and notepad all the time. They are very easy to use, and I have my life organized on the datebook. I read ebooks on it often (when I am in a line, or just somewhere that I can't bring a book), as well as playing a lot of different games.
If you are planning to use it to take notes or do any e-mail or writing, you might want to look into getting a keyboard, as it makes the PDA into something like a less expensive notebook for some things, but that will probably be something to look at once you get a device.
If you want to put office documents on the device, you will probably want something fairly recent, as most Palm and Sony mid-to-high end devices come with an office suite. Otherwise you will need to buy an additional software package, so make sure to check what software it comes with before buying a lower end/cost device.
There are several places on the web to look for more info, but I like to read:
www.palminfocenter.com
www.brighthand.com
http://www.geek.com/pdageek/pdamain.htm
for information and reviews. Let me know if you have any other questions, or think of anything else you would want to use it for.
-Lee
