I think this has potential to be bigger than just a computer for non-computer users. With a few changes I could see myself getting an ipad (and a lot of other people). At my job I have to print out tons of reports (as I'm sure many people do too) every week. I also have some reports that are too big to print. With the ipad I could put all the reports into this one device which I could take to meetings. This would give me access to all of my reports from the last year, two years, etc (which I obviously couldn't do with printed pages since that would be too many pages). In addition, I could have access to those super huge reports that are too big to print. And the best part is that since they would be in "numbers" I could search them, move stuff around by touching and dragging, hightlight things, etc.
The things that will stop me from pulling the trigger- No multi-tasking. So if I'm looking at a report and want to take notes at a meeting I'd have to close the report open the notes app, then close the notes app and go back to the report. I couldn't have a report open and a note taking window layered on top like on a laptop. The other issue, is that I would never take notes on this thing with the on-screen keyboard. I'd need a pen of some sort since it's just faster and easier. Now I know I could get a pogo pen or whatever that is, but I'm still not sold that the ipad will be all that. If it could do these things I think this could be a hit in some businesses and definitely in the education field (colleges, etc).
There are also a bunch of similar devices coming out. The notion ink tablet seems pretty ridiculous too...