Actually Mac is not an inferior OS. In some ways it is superior. How do I know? Because I have always had PC's for a little over 10 years, I've gone to college for networking, and started out using PC's. Quite frankly, I will probably always have a pc for my games and various programs. That said, I do use a Macbook which has the intel core 2 duo, and must say I am quite impressed. There are many great features of a Mac. For example, you can set up multiple network locations, example, if you had a laptop and needed to go 20 different places, you can have a location, or basically a profile set up for each of those places you travel to, go to the apple menu, and select where you are and it has everything done for you. Also, Mac is based on Unix, so you can use the command lines and customize. It also has a quite nice network utility, something windows needs to put in instead of the old command prompt.
This is from a guy that will always use pc's, and is using vista on an athlon 5200 x2 with 2gb of memory. PC's for me have the programs I want and need, and are great. Love them, but again, don't bash the Mac either, they have come a long way, and leopard is nice too.
Honestly, on Mac, it is a great OS, having used both I can say that because I have built PC's, and work on Macs at my job, which is about 90% Mac computers, in fact just got to take an lcd out of a iBook g4 yesterday, fun fun fun. But the plain fact is, what do you want your machine to do? If you want to run games and what not, go with Windows. If you plan on running lots of different software applications go with Windows. Windows is great as well, works with just about everything.
Mac, you'd probably have to hack the OS to even get it installed, have to order almost all your software. So that's a couple of things. That said, if all you need it for is a simple box to check your email, surf the web, do some word processing, just basic things an average home user would use a computer for, the Mac is a fine choice, you don't have to worry as much about viruses etc from what I've seen. Though in defense of Windows, they are getting better on that front. Mac is very very stable, at least my Macbook usually is, but again, I don't get many problems out of my windows box either. But people should not have a mindset that Mac is inferior or Mac stinks. I used to think that way, but when you mess with it, it's actually quite capable.
One feature I do like is that I have what is my expose feature. If I'm doing a lot of work, I can move my mouse to one corner of my screen, and it will show my desktop, move to another corner, it brings up a mini window showing what I'm doing in each application, then I can click whichever one I need into.