Ray, I would go with a laptop as well if we're looking at taking it on the WC. You can always buy a Mac laptop now and upgrade the OS later (very simple usually for Macs) though you will have to pay for it so if you want to get Leopard with your new Mac, you might wait until October.

The best cases for PDAs and phones are made by Vaja, I think. Made by craftsmen in Argentina, they're gorgeous with some amazing color choices and they have price tags that go along with that. But they're incredibly made. And yes, they do have cases for iPhones. Check them out here:
http://www.vajacases.com/

Masaki