[notabadname]

I think the MBA is a stand-alone product, as compared to an eventual MB replacement. It just gives up to many items to replace the broad-market appeal and value of the MB. Foremost, at the moment, I don't think the majority of users are ready to part with built-in optical. No need to list all the other differences again, but I don't see the mass-appeal yet for the MBA. It is an awesome machine, but for a very special market in my opinion. A market the MB majority would not switch too.

I would get my two kids MB's for school when needed, or if they were older for college. No way would I get the MBA's for them (or Pro's for that matter).

As for shells of Laptops, there are basic form-factors that will continue to dictate a pretty similar "shape" of laptops. You can swap plastic with metal, or maybe a carbon shell (becoming trendy in cars and aviation - light and strong), but even the MBA is a (beautifully) stylized rectangle. Until screens transform to thin film OLEDs that roll out on a spool, probably a decade away in affordability, we will have 12 to 17 inch diameter rectangular screens, and generally rectangular keyboards if we don't shift to iPhone like touch displays. And even with those displays, they will be rectangular, and only eliminate the need for the clamshell screen-keyboard format. Basically, nothing holds a bunch of rectangles better than a rectangle. I see the main change in thickness. Maybe about a 10% thinner laptop will be next. Significant for marketing, but not requiring "specialized" expensive engineering like MBA, and still fitting the optical drive.