I'm sure there will be a market for the Ipad - from the apple fans.
But I struggle to see how it would fill a void in my life.
I have a smartphone (which is also my mp3, video player, mobile web browser, ebook reader and unlimited data 3G modem for my netbook) an N97 BTW as I wanted something different to an i(only do one thing at once)phone.
A netbook if I want to do more heavy browsing, edit a photo or a short video, upload gps waypoints.
A full laptop for longer video editing and more intensive tasks.
An ipad is too big to replace a smartphone and can't run any software not authorised by apple, so dispite having 5,000 fart generators and games and a limited number of useful apps your unlikely to find a massive amount of the more obscure but useful apps. ALso the lack of a camera (even a built in web cam would be useful for skype calls) and the lack of Flash protocol in the browser are not good signs.
If used in addition to a smart phone, to get any real use out of it would have to be the more expensive 3G enabled (plus an additional monthly / pay as you go network bill).
On the 3G point am I being cynical when I think that Apple, dispite selling them unlocked, have designed it to use a micro sim card so you can't just put your phone sim in it? or is there another benefit other than reducing bulk.
However having said all that if I had to replace the netbook I would probably be holding out for one of these: