Making products thinner and lighter is the path most developments take and this is what is happening in mobild computing too. I would see it as a next step in laptops but hope they don't mimic the tablets because that would mean taking aways the high computing power a laptop meant as a portable computing device.
there's space for a variety of mobile devices. today's ultrabook is just fitting a "premium netbook" niche, which is fine - it's a valuable use-case. it's not the same use-case as tablets, though: they're are more of an appliance, less general-purpose, not suitable for serious typing, more for reading, less for multitasking. that's not to say that touch wouldn't be welcome on ultrabooks (actually, the big improvement there would be higher-quality IPS-type panels.)
It would be keyboard, performance and industry standard software. The line is certainly thinning.
I'm anxious to see how the "instant on" really works. That feature has been promised for a very long time. I've yet to see it on a Windows device.
"...or should I say MacBook Air clones with a Windows operating system." is an unfair statement. Various brands introduced thin laptop computer long before MacBook Air came to the market. A lot of high end Windows based PC from Sony, Fujitsu and Toshiba are lighter than MacBook Air.
Just over the weekend, I have stopped by Microsoft shop to check out various PC. There are various impressive notebook computer although I have hard time differentiating ultrabook from regular notebook computer. A PC of 2.2 lbs with full HD screen is an ultrabook or is just a notebook computer. I have seen another PC which is comparable to 11" MacBook Air. It costs $100 less. The industry design is impressive and the choice of material is perfect.
With the experience, I believe, for Ultrabook to be successful, better differentiators have to be introduced. Light weight and long battery life are just some of those. Consumers are looking for more.
Only four PC OEMs have introduced the thinner, lighter, sleeker notebooks to market.
--- Making the product thinner, lighter and sleeker is not the only thing that will help, it's mostly about the power and performance. And then comes the commercial aspects of it, will it be cheaper compared to ARM based products, and then comes Business models, whether intel keeps their OEM's tied to their trends or give the flex to add their own stuff on it.