I agree it is very unlikely weíll see OS X run on PCís. Itís something Jobís has protected (at a huge cost) for years. But itís not impossible.
As for buying now or later, well as far as the software is concerned, by the time all the Intel stuff is out, everything should run pretty well. I KNOW for a fact that Photoshop runs just fine under the Intel box because our engineering dept (for Pixel Genius) has one. Developers have had access to this hardware since the time Jobs announced the new chips.
Last ďrumorsĒ were by January, we might see the first boxes with the new chips. Donít know if that will be laptops or desktops. However, if you need to run things, now, buy now. For example, I just decided I needed a newer, faster Powerbook. Iím not sure I want to own the very first Intel Laptop (although Iím sure itís going to be fast, cool and Iíll probably eat my words). From the standpoint of the OS, I doubt we will notice much if any difference so if you need time to get up to speed on OS X now, go for it. Many PC users who move to OS X seem to do fine since they are used to ďgetting under the hoodĒ and since OS X is Unix based, you can do all this if, IF you wish.
All the heavy lifting for Aperture is done with the video card so I expect the new quad processing G5ís just announced will scream. When I get my reviewers copy, I fully intend to see how it preforms on my 1.67hz G4 Powerbook as well as my 1.8 ghz G5 desktop. Neither are considered quick by modern standards (not to self, need to buy new, faster G5 desktop <g>).