I develop software for clients that run on Pocket PC and/or Palm, so that's the only reason I own one. It's too expensive ($600+ for my iPAQ at the time) and too large to carry around with me everywhere. Paradoxically, it's too large of a device yet too small to do the things I'd really want with such a device (i.e. I'll use my laptop).
I want a VERY SMALL device for extremely primitive things (contacts, appointments, email, etc.). I really have no need to browse the internet on such a terribly neutered screen. If I want to hop on the net, I'll grab my laptop.
On another note, I've developed software for the Pocket PC for use in inventory/receivings, purchasing, etc. and it works great for them.