I think that we have determined that it all depends on how much computer knowledge you have and how much you monitor every aspect of your system. If you notice, most people who are at the top of the computer programing world use linux systems because its free and completely customizable if you know what you are doing. The average user will use windows because it is cheap and fairly easy and, for all practical purposes, they would not notice the difference between 95 and vista. Power uses, which we shall define as someone who needs performance but does not want to have to babysit it, in the photography world will be best off with a Mac as they have very few problems when you just let them be. Then if you are pretty good with computers, but do not know how to program all the functions you want yourself, you should go with windows as it gives you the most options and its hardware is dirt cheap. If you get a MacPro, you can build the same system, but double everything for the same price (single quad core->2x quadcore, 4ggb->8gb, no raid->raid, and so on). I have yet to see any performance comparison between a pc a double the specs and a mac, but I hardly doubt that the all powerful OSX will be able to pull that one off.
The only time the fairly good with computers group should own a Mac is if they are working on a project where everyone else is using a Mac, (usually in the video editing world), just to make life easy. Final Cut Pro is pretty darn great for the price as the only other software that competes is Avid at 2x the cost.
My PC which I built myself has a 50% overclock and is completely stable, has no bloatware running, and has not crashed since the initial overclock testing 2 years ago unless I did something really stupid, like delete a critical system file, but since all of my files are on a separate drive, I just reinstalled and within the hour, I was back up at full power. And since I created a reinstall disk with my ideal setup on it, I do not have to worry about the reactivation.