Sorry to be another newbie who's first post is to ask for help but I've been looking for an answer to this question for the last month so here goes.
I'm looking to buy a cheap PDA, around the ?200 ($300) mark. All I need is for it to write/edit Word documents on the go and for an organiser. Other gadgets would be a bonus but still the most important thing is that I want one with a user-replaceable battery, I don't like the idea of having to send it away to get repaired.
Pretty much all the current PDAs with user replaceable on this site would do the trick. For Pocket PCs, look at the table at the bottom of this article, which shows which current models have replaceable batteries: http://www.pdabuyersguide.com/tips/pocketpc_2003_comparison.htm
If you get a Palm OS PDA, make sure it comes with Documents To Go for working with Word and Excel files, otherwise you'll have to purchase it separately. Though most Palm OS models don't have user replaeable batteries.