There's been a lot of speculation flying around recently concerning Apple's switch to Intel processors and I figured I'd throw my hat into the ring so that years from now people can link back to this and see how wrong I was.
Here's what I think will change: Nothing. Zip. Ziltch. You'll be making snowmen at Hitler's house before Apple even dreams of letting MacOS X run on commodity hardware. This makes Apple no more a threat to Microsoft than it's already been. This will not take focus away from Linux on the x86 architecture. Apple will continue down the path it's been on since rehiring Steve Jobs eight or nine years ago and retain a stranglehold on what machines their operating system is allowed to be put on. You will still only be able to run a Mac OS on a machine produced by Apple. You won't be downloading a pirated version of (or buying a copy of for that matter) MacOS X Tiger for Intel and installing it on your Pentium III. Ain't going to happen.
Now, as a tip of my hat to the dogged determination of hackers around the globe, I'm sure projects here and there will pop up on SourceForge explaining ways to actually get it running on commodity hardware. I also believe such projects will either be shut down by Apple, not have enough hardware support to be practical, involve instructions too byzantine to be followed by mere mortals, or a combination of all of the above.
So there. Pirates, you ain't getting MacOS X on your junker. Mac zealots, your precious gene pool isn't being diluted with "Wintel" slime. Douchebags, you will still be able to buy a cool looking computer that you don't really know how to use. I'm even sure that they'll rename the PentiumD they use to the Granite-X, the Cube-4D, or the the Strawberry-Douche using whatever gay ass formula they use to come up with their For-Marketing-Purposes-Only, quasi technical sounding names. Of course, not that the name "Pentium" has meant jack shit in ten years.