Will the ipad actually be useful for the things people actually need to get done to do their jobs? and contribute to a better world because of it?
I think in very limited cases it will, but will mainly help non technical people consume more media.  Is this a good thing? I personally think not, because I like nature too much.  I am happy that some people do not spend their life glued to a screen. Others may differ on this.
In terms of useful applications, for doctors and for others who need convenient information retrieval, the Ipad will be great, and I welcome it.  
On the most part though it will just be a gadget that people will get addicted to and waste more or their worthwhile lives on.  Real work will be done on real computers (with a keyboard).