The only other large group of people I know using MacBooks are developers who wanted a desktop Unix that IT would be willing to support. With the loss of the function keys and the abysmal max memory spec, the new MacBook Pros are worthless for that crowd. They might be pushed towards Linux, but with Microsoft starting to push Linux dev tools into Windows, the "IT supported" requirement probably means they'll hook back to Windows instead.
Its not just IT... Its also commercial software vendors who make things we all sometimes need to use, even if not as our primary tools.
Regardless, I've often felt that this is a surprisingly large/significant market for Apple products that Apple themselves seems willfully ignorant of. I've even felt that the growth of this market was at the significant expense of desktop Linux. Heck, come out to Silicon Valley sometime and just look at how large a percentage of software developers are using Apple laptops.