I had an HP Jornada 690 for a while before it met with a very unfortunate coffee disaster. It was a great little gadget, having probably the most usable keyboard that has ever been created at that size. It was better in many ways that a PDA with a wireless keyboard - it was mroe stable to type on/less fiddly. I loved it, but at the time they were quite expensive, so i didn't replace it.
If you picked one up cheaply, I don't think you'd be disappointed, unless you're looking for modern features like Bluetooth or wireless built in (I think you could buy expansion cards, but they're probably not worth it). They tended to be the best litle gadget for spreadsheets, due to the larger screen size, but they were less "pocketable" than most PDAs.