I seldom leave the house without my iPod, my PDA (Handspring Visor Prism) rarely gets a look-in.

The iPod has names and addresses, calendar, and notes (and something to do with data storage, and mp3 capability :)

Of course there's no way of entering data directly on it, but I'm usually close enough to the net so I can update my .mac addresbook/etc from anywhere, and sync it when I get home.