The answer to the original question is highly dependent on what you plan to use your computer for.
I develop game technology and tools for both PC and Mac. I develop and work on both. I
very much prefer Windows. Now this comes down to my needs:
1) As far as gaming goes PC is a no brainer... there are those that will argue emulation on mac (or Linux) of Windows, but this loses any argument of mac "ease of use" that might be won.
2) I've used Macs for a long time though I've used PCs more. What you are used to will dictate how easy it is to use in 99% of the cases. If you take a PC user and throw them on the mac they'll typically have issues, vice verse. I've seen this many many times. The argument of which one is "easier" is typically a farce put forward by those who have a bias and don't recognize it as such.
3) As a software developer, specifically game software, Windows wins out hands down. The developer tools on a mac simply can't compare. I do in fact use the developer tools on a Mac since the products I work on are typically cross-platform, so unfortunately I have to know the developer tools on both. Hands down Windows wins here (Visual studios triumphs over Xcode basically, but it comes down to many more things than that as well).
4) Ease of use... like I said this primarily comes down to bias. You can get used to either and work well in either. Web browsing, document creation, e-mailing, and web games are more or less equal on both. There are very few things I can point to that a mac can do that a PC can't do, while I can point to gaming on a PC while many games are not put out for the mac... Outside of that I'd say they both are more or less equal. Using both I still prefer windows any day, I find the mac interface confusing and clunky compared, while Windows I find tries to do more for you but sometimes fails because of that *shrug*. This is a very opinionated topic so you'll hear different things from different people.
5) Price... this is the biggest deterrent in my book. PCs can be bought with equal or greater power considerably cheaper.
6) Irony... ironically one of the biggest current features of modern macs is you can dual boot windows on them. A lot of gamers do this. This is ironic in the extreme and it always gives me a laugh. It was a smart choice by Apple and I know many people who own macbooks and do this.
7) Stability... you will hear something different from just about every single person.
gotorightway123's statement
is definitely true. There are many more PCs out there hence it's a bigger target. This is simply the truth of the matter, hackers will simply target the larger mass media base, a pretty duh thing. You can use this to your benefit and have a Mac, but understand that this is indeed one factor of it. It is
not the only factor.
I would agree with the above post to a point. This security comes at a cost. The biggest annoyance of Vista... UAC which is a pretty strict security feature. This is an issue mac and linux users will always face. Security nearly always comes at the cost of usability. Windows Vista realizes this with UAC (fortunately a single setting to disable). Most typical users will trade security for usability, though there's a balance to be had.
On Windows, if you are careful (avoid porn sites and the other common sense things), and run some free security programs you should be fine. It's not that big of an issue these days.
8) Hardware options... you simply have an abundance of hardware options on a PC, partially why it's cheaper, so if your into getting hardware specifics you may be very unsatisfied picking from the limited mac options.
Keep in mind everyone has their own opinion, both Operating Systems have their pros and cons and both do things good and bad. They are equal on quite a few levels as well.