CNet is again reporting that they have heard strong rumblings that Apple will announce on Monday a switch to Intel-based CPUs in the Macintosh line. I'm skeptical, but we were all skeptical when people discussed the switch to the PowerPC from the 68xxx architecture in the early 1990's, so we'll have to see on this one.
Personally, I don't like the idea. Sure, AMD does make a nice architecture, and one that Apple could likely leverage because of the use of the HyperTransport architecture, but there are some inherent benefits of the Power architecture that appear to be a much nicer fit over the long run.
Especially with articles, such as the one referenced this morning here, about OS X still needing some work in the thread management area, it'd be a shame to see a move away from the Power architecture and lose all of the Altivec benefits.
With all of that said, there are some big differences between the move to the Power architecture from MC68xxx and the potential move to Intel now. Most importantly, Darwin, the core of the Macintosh OS, runs quite nicely, thank you, on Intel processors. There has been an effort by Apple to keep their options open in this area, and it provides (at a minimum) a credible threat to IBM.
Also, there has been a strong move over the past few years to move all of the bits and pieces of the operating system that were hand-coded in assembly and other architecture-linked ways into C, C++ and Objective-C, which makes them substantially more portable. Further, the decision to use --and help maintain --the toolchain using the GNU compilers makes compilation of code for IA86 processors a snap.
Further, much work has already been done to move to a 64-bit clean environment, allowing the use of AMD's x64 processors (including the dual-core and multiprocessor variety).
Yet further, many of the recent optimizations involving the use of GPUs for additional processing would also carry forward to other architectures.
SO, I'm not a big fan at this point in time, but it wouldn't be the end of the world either. As long as Apple continues to make hardware. A wholesale switch to providing software without hardware would be a bad idea.