Had a palm III, a Palm IIIX and a Palm M500.  The M500 (or the colour version (505?)) is a pretty nice unit, it's small, fairly light, and has built in rechargable batteries.  If you figure you will be using it a lot or attaching components (keyboard, camera's, modems) then the rechargable batteries will more than pay for themselves.
I depends on what you plan to use it for though.  Skuzzys example is great. I often attach a folding keyboard to it and use it like a laptop to write emails, memos, or almost entire documents.  It's perfect for that sort of thing and is about 10th the weight of packing around a laptop.
-Soda
The Assassins.