The iPad is the next Mac. The iPad is the future of computing. These 5 articles say it better than I can:
There are many people that use computer out of necessity, but don't understand them. Often, they fear or resent them. The iPad is a computer that doesn't ask them to become conceptual computer people to use it.
My 2 year old can use my iPhone without instruction. She can launch games, and play them. The iPad is equally discoverable.
We nerds will cling to out windowing systems, our terminals and our customized interfaces. We will add the storage we want, and push the envelope of configuration. Everyone else will enjoy a simple computing device that lets them accomplish their tasks and then move on.