I don't think the problem with the success of tablets in the marketplace is as simple as the clichéd "Windoze sucks" mantra.
Typing on a keyboard with a stylus is just not a natural way of entering data to a computer. And handwriting recognition systems continue to remain sub-par at recognizing input the way people naturally write. Sure, I can train myself to write in a certain way at a certain speed to allow the software to have the best chance of correctly interpreting what I am writing, but that defeats much of the perceived benefit of being able to "write" on my machine.
Tablets certainly have a market, albeit a small one. And multi-touch keyboards will help by allowing people to type with their fingers (however the lack of any tactile feedback will likely result in a high error-rate). But I just don't know of a feature (or feature-set) in OS X that is so compelling when executed on a tablet that it will immediately drive the sale of a million units a quarter - which may very well be what we're going to need to see for Apple to launch the product.
Only 1 thing I beg to differ..... Look at HP's new touch smart with Vista Ultimate/Home Premium SP1. I know a lot of people are drooling over that right now. and it is only $1100. Yes it is a desktop and not a laptop, but if you watch some of the Youtube videos of it's uses in the home, rather than
being tied to a desk. it is advertised as a whole home automation, organization, entertainment device.
I actually played with one at Office Depot while picking up some supplies. It was nice and the handwriting recognition was at 97% using my fingernail. Only certain MS apps support the handwriting recognition, not like Apple's inlwell where every Apple app and use the recognition.
But yes, I have heard even some glitchyness with SP1 on a tablet.
I also think that people using front row could use it as well. Just think of a remote without buttons that you swipe with your finger to find what you want (like on the iphone).
I have a wacom tablet now, and with the work of Axiotron, I see Apple making it a BIG success.