Mac on Intel
The big thing to watch for is not whether Apple is going to start using Intel (and/or AMD) CPUs; it is whether Macs will continue to require Apple ROMs or other components that are not going to be available to 3rd parties (either other system builders or hobbyists).
My 2cents? Steve is not going to allow clones. They tried that once before, and one of the first things Jobs did upon returning to Apple was to kill the clones.
They might be able to pull it off - allow 3rd parties to make systems that run OS X, but compete on the basis of killer hardware. But I doubt Apple is constitutionally capable of going there.