One thing I haven't seen the "cloud" solve is offline users. I have sales and marketing people that do a lot of work on airplanes, trains, and automobiles. They still need offline access to word processing and email so a dumb terminal or even a tablet based system isn't going to work for those users. Yes you can get a tablet with wifi or cellular data but that isn't 100% reliable while you are traveling.
I had an account rep that insisted he needed an iPad, that it would do everything he needed through cloud until I asked him how he was going to work on email with it on the train that didn't have wifi or spotty cell service. He decided to keep his laptop.