technical questions

I'm looking for a combined phone/PDA/MP3 player - preferably Windows-compatible since I'd like to be able to adjust Word docs without carrying my entire laptop around. Something that's solid and not too fancy. I've asked around a little but there are so many options, it's quite intimidating.

I may need to revise my current mobile plan - it's not bad, but it's not fantastic either.

Recommendations? Suggestions? Pointers to site that might suggest models and makes?

Does anyone use a multifunction mobile phone (cellphone to the Yanks) or know of someone who does? How do you/they find it?