Matt Gemmell echoes my feelings on the iPad as a productivity device:
The oft-repeated fallacy that the iPad isn’t a tool for productivity and creation has no credibility whatsoever. Anyone trotting out that old chestnut is either labouring under some astonishingly wrong-headed preconceptions, or is making excuses for their own failings.
I manage to be very productive indeed with the iPad, and I don’t have to jump through many hoops to do so. With the right set of applications (and more are becoming available on iOS every day), you can get real work done - effectively, pleasantly, and regardless of where you happen to be.
I wholeheartedly agree, especially with the first part.