IMHO....
For simple applications (address book, diary) then I'd go for the Palm, mainly due to the battery life (my fr**gin iPAQ died after a week unused in my office desk over Christmas). If you need to do more than the basics and can put up with poor battery life the iPAQ is much better - mine is almost as powerful as the PC I had five years ago. I use it for all sorts of things, but I'm paid to.
If you can splash out a bit of money then an iPAQ with wireless ethernet (or bluetooth) is almost great. In an ideal world add in the cost and battery life of a Palm and it would near perfect, but we're not quite there yet. Battery life sucks even more, but it is wonderfully integrated with your desktop machine.
edit: pocketWord is sodding useless for anything other than very short notes. You cannot 'word-process' on it. pocketExcel is just sodding useless. IMHO
