Also, if OSX goes to the PC platform, what affect will that have on the Linux platform? Many, many people use Linux simply because it is not Windows. If they have another viable option, other than Windows and Linux, I don't think that it is going to be good for Linux. Sure, there will be many hardcore Linux users that stick with it, but I think the majority of the users would consider OSX.
No, most Linux users us it because it is
FREE (and not just in that it costs no money, but also in that there is no restrictive EULA that forbids you from looking under the hood, tinkering with it, or developing software based on the core components ... as long as you release it under the GNU license).
The downside of this happening is the potential for Windows malware to be able to infect Macs.
Windows malware infects Windows machines because of Windows, not because of Intel.
Macs are going to be just as vulnerable to malware as Unix and Linux are (which is not very much) because Mac OS X
IS BSD Unix. Unix and Linux are just more secure (for one thing because you have to manually enter a password to futz with the inner workings of the OS).
Of course if you buy a new Mac and dual boot with Windows, there's nothing protecting your Windows partition :p
Ultimately what we're seeing here is the beginning of an age where software is not hardware dependent.