My one and only PDA is a Handspring Visor Deluxe. I used it to learn Pocket C, then I said WTF is the point these things are crap, my brain can remeber all my appointments and phone #'s (phone book is cheaper if I forget #'s).
Just my personal opinion though, I do see many uses for PDA's in business, just my experience that most businesses here find PDA's a hassle rather than a help (I hope its better for US companies).