Another grenade lobbed in the ongoing Mac/PC war.
Having used and supported both, I have certain issues with each - both in use and in maintenance. I respect both PCs and Macs, though each has its own niche.
In terms of use, my experience is that Macs are not as well suited to software development (primary experience is C / C++) or gaming as PCs. PCs, on the other hand, aren't nearly as good as a Mac when it comes to multimedia development. If I'm coding, I want a PC. If I'm doing A/V work, I want a Mac. If I'm gaming, I kind of *need* a PC (not Mac's fault - mainly that I've seen a lot of software houses shy away from Mac porting to take more advantage of PC deployment).
In terms of maintenance in software, Mac has the lead - simply because there are infinitely fewer malware issues with a Mac. Basically, Windows sucks.
In terms of hardware work, PCs are king. If I want to refit a PC, I can buy anything I want from anybody I want, open the case with a screwdriver, plug stuff in, and it just works once the drivers are installed. Macs, on the other hand, are a closed hardware system (or were, until Intel got into the Mac game - more on this once I actually work on a Mactel machine). ONLY Apple makes the hardware, which means your incremental upgrade path with a Mac is severely stunted, as opposed to the open standard of PC x86 architecture. And common varieties of Macs are not user-servicable, requiring breaking into the chassis (iMacs) or using a special case-cracking tool (a lot of the PowerPC variants I've seen) to even open the box. As a hardware guy, I hate that - I can't stand it when a company goes to such lengths to keep me away from the hardware. I buy a Dell machine, I unscrew one screw, push a tab, and I'm in - 10 seconds flat. With a Mac, I have to hope that either it's a screw-in non-sealed machine, or that I happen to have a slim-jim (the tool, not the snack) to crack it open.
But I'm mainly talking hardware archietectures here. In hardware, Macs are superior for media processing, if you don't mind having a "black box" computer. PCs are superior for ease of maintenance and upgrade, so long as you don't mind your machine being "good at a bunch of stuff, expert at nothing". It just depends on where your priorities are.
But now we get into software - the operating system.
OK. Windows is crap, but it's highly available crap. Most software apps are built for Windows, meaning your Windows toolkit will be larger by default. You can do more with Windows, but not as well.
Mac - again - is a multimedia system. I haven't played with OSX yet (I know it's based on BSD UNIX, which earns a TON of respect in my view, but I don't know it personally). My main problem with MacOS is that it keeps you away from the "bare metal" of the system. Even in Windows, I can get an unrestricted command-prompt and do things that aren't supported by the GUI. In MacOS 9, no such animal - you're constrained to the interface that Apple provides for you, and can only go outside that if you're a master wizard (like Vinny, the best Mac op-tech I've ever seen).
Linux, the "third child" of the OS world, is my preference. It does everything equally well, is completely non-specialized, and can be learned openly (since the software is open-source, anybody can do pretty much whatever they want with it). I like Linux for its stability (the US gov't rates it as the most stable and secure public OS out there, and I've found that to be true in live-use) and it's "hey, I'm an infinitely big toolbox - I can do whatever you want, just plug it in!" modular nature.
So, in summary of my opinions:
Macs - "user-proof" office apps and high-end multimedia work.
PCs - upgradeability, gaming, server-level apps.
MacOS - same as above.
Windows - gaming and expandable office apps.
Linux - server apps, development.
In my ideal world - everyday home-users use Macs, offices use a mix of Macs and PCs as determined by the jobs of the users, and the servers are all PCs running Linux.
