There has been alot of speculation regarding Mac’s switch from IBM to Intel chips. In his usual discussive way, Daring Fireball suggests that it is distinctly possible that the Mac is changing to x86, though I think that possibility is out of the question.
It’s reasonably obvious that some of the industry powers (Microsoft, Sony and Nintendo) believe that the PowerPC is a powerful processor with their use of it in their next generation consoles. It’s interesting though that gaming consoles don’t need an avenue of improvement due to the fact they won’t be upgradable.
The other reason I believe it won’t be x86 is 64bit. The Intel chips aren’t 64bit at the moment and there is very little reason to change to a whole new platform that isn’t 64 bit, Apple can leverage their entire control of the platform and hardware (not to mention the Unix underpinnings) and move to an entirely new level of performance that no other hardware platform can produce. If it is a move to 64bit, I wonder why it’s not AMD.