[joev]

Consider that Apple has neglected the non-Pro MacBook for quite a while: it still uses a Core 2 Duo processor, and the MacBook Pro line includes a small-form-factor 13" machine that uses the i5 and i7 chips.

If this rumor has any legs, I can definitely imagine Apple moving to ARM for the MacBook Air and MacBook, to which will greatly benefit in terms of battery life and size along with its iPhone, iPad, and Apple TV bretheren. Most of these customers will be using the App Store, so the "fat binary" problem is probably much less of an issue, since Apple can mandate that submitted apps must be bundled for both platforms, which shouldn't be much of a problem if XCode supports it. They will remain with Intel for the MacBook Pro and desktop lines, for customers who need the CPU power, and are less sensitive to power usage.