Most Mac proponents will rave about how good it is, and how much better it is than the windows PC. Seriously, most of them are looking at things through tinted glasses.
Even before Mac switched to using CISC architecture, they have been yakking about how much better it is for professional applications, how much more performance you get... but in the end, still switched to x86. Now, PCs and Macs are based on similar hardware. The only differentiating point is the branding, and the software.
It's true that the Mac OS does not suffer from many viruses etc... this is simply because few people actually write viruses to attack Mac. Fewer people use Mac, and virus writers usually want to affect as many as possible. BUT, if you're gonna use Bootcamp, your Windows partition is still going to get these nasty malware without necessary precautions.
Myth - A Mac is faster than a Windows PC. This is definitely not true, and has never been since the PowerPC days, despite the benchmarks provided by Apple. Now that Macs are using x86 CPUs, the performance is roughly equal on the same hardware. That said, it must be noted that it is generally easier to upgrade your PC. Some sore Mac fans might disagree, but it's true.
Myth - There are more Mac applications for graphics/sound. This is again, not true. The Mac comes with free GarageBand, but that is not really meant for professional use. If you really look at the applications available to Windows PC, I think you'll agree that the Windows OS has more choices when it comes to real professional tools. There is a reason why most animators use Windows PC.
Sure, if you need to, you can dual-boot your Mac and use the Windows OS - in this case you get the best of both worlds. But of course, that also means you get the worst of both worlds.
Myth - Mac OS handles graphics better. The truth about graphics is: it depends on your graphics card. You pop in the latest graphics card on a 3-year old PC, you get much better graphics than the latest MacBook, which often uses only the integrated graphics (very slow compared to a dedicated card). No surprises - the gamers use only PCs.
Myth - Mac OS handles sound better. If you are looking at the professional level, ASIO works the same for both Mac and PC. If you really study how ASIO works, I'm sure you'll agree with me. For professional sound work, this is a level playing field, i.e. there is not much difference between using PC or Mac. There is probably better driver support for the PC, though. So you better check that there is good driver support on the Mac for your audio interface.
Myth - Windows OS is very unstable. Hmm... Windows Vista maybe. Most users are happy with WinXP SP2 stability. Don't buy into the Apple marketing of "It just works". WinXP SP2 just works too! There is a good reason why it is the de facto standard OS. Actually, Vista is also not unstable, it's just slow.
Myth - Windows cannot sleep/hibernate/poor battery life etc. This is simply not true.
Fact - A Mac is generally considered to be less upgradeable, so if you're looking to change a HDD, add more RAM etc., Windows PC is the way to go.
Fact - There are more software and driver support for Windows OS (XP, not Vista). But of course, also more viruses etc.
Fact - Audio work is pretty much platform independent. Most VSTs plugins work equally well on both platforms. Sometimes (just sometimes), they are optimized for the Win PC. If you have done any signal processing coding and compiler work before, you'll know what I'm talking about. Also, almost all plugins in recent years are designed on a Win PC (usually coded in / integrated into MATLAB).
Fact - A Mac can enjoy the "best of both worlds" - if you really need both OSes, you can always dual-boot. But with it comes the "worst of both worlds", so you got to be a little careful.
Fact (subjective) - The Apple Mac designs looks way cooler than any PC can ever be. But it comes at a higher price, for equivalent hardware.
The choices:
Exclusively Mac OS: You lose out on a lot of software choice. But you suffer only few malware. You get to show off to all your friends how cool your computer looks.
Dual boot Mac+Win: You get the software choices of Win OS, but get the malware as well.
Exclusively Win OS : You get more software. You have better upgradeability, things are slightly cheaper as well, but you may run into more malware problems.
Bottomline:
If you want to be cool, go get the Mac. Best is MacBook Air. It's so thin I fear I might break it with 2 fingers. Dual-boot it to be even more cool. Recommended for designers and fashionable people.
If you want to play games, get the Win PC.
If you want to do serious graphics work, get the Win PC.
If you want to do serious sound work, either is fine; but before you get a Mac, check out the drivers first just to be safe.