Wow. Let me just say (from the conversation so far) that the replies here have been both open-minded and helpful. The last few threads descended very quickly into anarchy --- good job folks
My wife has an iPad2 and the only thing I would say that it is missing is a native SD slot (which wouldn't help CF people, but you get the point). MarkB --- what accessory are you using to transfer images? I saw another photographer using something, but it was REALLY slow.
I have a MacBook Pro (the wife has a Win7 laptop) and I have to say that my vote is the MacBook Air, or a PC equivalent. Something that has processing power, but is miserly with the battery. The one edge that the iPad2 has over the MBA is the built-in 3G, which wouldn't be for photography so much as making it more usable on the road.
It will be interesting to see the Windows offerings with the Ultrabook project . . . Win7 is a good platform, let's hope they don't mess up Win8 where they 'will take the new release in a very different direction'.
These are just my opinions but worth every cent paid