Ars Technica has an interesting article about the potential market and purview of Windows 8:
I can't help but feel this article is rather missing the point of a tablet, and also the limitations of technology at present.
Use Case: I want to edit a complex Excel document for a presentation.
Requirements: Highly portable device, long battery life, fully functional keyboard, pointing device, sophisticated user interface, rapid software response rate
Can a tablet meet this use case. No. And here's why:
Slow CPU (comparatively)
No pointing Device
Let's look at the last two, as it's reasonable to challenge those. No pointing device, and no keyboard. You can have a keyboard and pointing device connected via bluetooth. But why would you want to? Even Apple's super slim keyboard design isn't all that compact, and a mouse isn't very compact either, being rather fat. Now you need a bag to carry these accessories and this solution is looking considerably inferior to a light portable laptop.
The best solution to this use case is a device like the MacBook Air. Why?
Long Battery: check (relative to other laptops at least)
Pointing device: check
Full Keyboard: check
Sophisticated UI: check
Rapid software Response: check
Economically, if you're doing this, you probably don't have an entry level iPad. MacBook Air starts at $1000, and iPads top out at $850? The Air has dramatically more power, storage, screen real estate. Better keyboard, trackpad, and isn't all that much heavier.
The cost difference just isn't that big given the functional difference, and if you're a business user with this requirement, I'm guessing even a $500 difference is bordering on meaningless.
If this is really the functionality you want. Buy a laptop, not a tablet.
Add on the other use cases that this kind of user has, and the tablet isn't really a contender at all. How often would a tablet form factor be better than a laptop for this user. Hardly ever. This user doesn't want a tablet that's also a laptop, they want a laptop that's occasionally a tablet. They have these if that's what you really want, they're laptops with touch screens.
One device simply cannot rule them all. That's life. There's a reason there are 60 kinds of Spaghetti sauce at the grocery store. Different people like different things. The really sad thing to me, is that there are 60, not 20, which would satisfy the market, and leave room for different kinds of items beyond spaghetti sauce that would also appeal to a customer.