First and foremost, it's Apple iPad. Not "Mac iPad."
I think that $630 is a bit much for what you get. Yes, there is a $500 version without 3G but at that point you might as well save yourself a few hundred bucks and go with an iTouch or iPhone.
People will buy this because it's got Apple written on it, but I don't see this thing revolutionizing the industry. Regardless of how much Steve Jobs hates netbooks for their disadvantages, I don't see a $630 tablet competing in the same category as a $300 Netbook that can do more or less the same thing.
What interests me the most is the CPU in this thing. Very power efficient for sure. My best guess is that Apple will update the rest of it's mobile lineup with these CPUs since they basically beat everything else on the market in terms of power usage. Hell, maybe one day we may see something like a Macbook Air with a beefed-up version of one of these in it.
Also, the cheap 3G is very attractive. My guess is that Apple demanded that AT&T either reduce the cost of its data plan or improve the quality of its service in busy areas. Hopefully this will be transitioned over to other non-Apple products, but I doubt that will happen in the short term.