why x86 rumors
The reason these rumors are so persistent is because Apple's boxes are so incredibly slow. AltiVec is better than 3DNow but not THAT much better. PowerPC is faster per MHz but not THAT much faster. All in all, an x86 Mac would be so much faster than today's hardware at the same price that it would make a Mac-lover cry.
And I don't know why people assume an x86 Mac would be a generic x86 box. Of course it wouldn't; it would be an Apple Mac with an x86 processor.
Yes, the transition would be difficult, which is why this will unfortunately not happen soon. However, my assertion has always been that Apple really needs to move the xServe and MacOS X Server to x86, or x86-64 or IA64, as soon as possible, but that the desktops can't move yet because of application software compatibility. Server software has the insanely high margins and "compile and run" mentality required to make it feasible. Home users just want everything to work unmodified.