I could never use such a small screen for 'serious work' but it is useful, particularly when travelling, to read ones email, and it can also be used as a phone with almost any VOIP client and a headphone. On a long flight for instance, one has it as an alternative source of movies and music.
I've read on other forums how people are using them to control their digital media collections/appliances quite effectively, so they have lots of uses.
I also have an old Dell Netbook but far prefer to use the iPad as the screen is so much more easy on the eyes and the unit is so much faster.
It will be interesting to see how fast this new tablet will be using a regular OS.
