As an avid Mac user who works in a technical field with technical people, I find myself in Mac vs. PC debates quite often... and sometimes they get surprisingly heated!! I always end up defending myself against the typical rhetoric, so I've been working on an argument that basically addresses what I think is the crux of the whole debate; Kind of long, but Feedback is appreciated. 
It all boils down to open-platforms and closed platforms;
A Windows PC is an open-platform computer which means the operating system, Windows, is designed with an open-ended approach to all the hardware, leaving much of the configuration to be done later, on a case by case basis. This allows for many manufacturers to create any individual components and anybody can assemble these components in almost any configuration, install Windows on it and you've got a standard user-experience computer... There are three main benefits that are exclusive to this dynamic;
1) an open, competitive, free-market of hardware manufacturers which helps drive innovation and keeps prices in check.
2) an abundance of configurations, models and options to choose from or the ability to custom build a personalized configuration.
3) a modular design which grants the ability to upgrade, expand, tweak and optimize throughout the life of the machine, as new technology comes available.
To a lot of technically-minded people, these three things are considered basic computer freedoms, like the inalienable rights of consumer technology.
From this perspective, a closed-platform system, like the Mac may seem fundamentally restrictive, backwards and even oppressive to it's users when compared to the 'openness' of the PC world... specifically in the three areas mentioned above:
1) there's no open-competetive market of manufacturers to help drive prices down.
2) At any given time, there's only about a dozen basic configurations of Macs being manufactured which pales in comparison to the thousands of PCs to choose from.
3) Macs are not "modular" and typically have very few upgrade options. They're designed and sold mostly as singular cohesive products.
However, the advantages of the Mac come specifically from this "closed-platform" approach. Advantages that come from running your operating system on the EXACT hardware that it was specifically designed for. Advantages like engineers being able to tweak and optimize the performance and configuration of every component from early on in the design process rather then leaving that responsibility to the user. Bugs and conflicts can be worked out on the assembly line rather then expecting 3rd party manufacturers or tech-support work out these details. By designing all the hardware together, in tandem with software it affords the ability to streamline and optimize efficiency from the ground up in a way that an open (or "hands-off") system just doesn't have the luxury of doing.
Additionally, because any Mac you buy is exactly like thousands of other Macs out there, it means Apple has to answer for each and every one. Being accountable means that they're concerned with the quality of materials and take great care to make their products live up to their brand name. When problems arise in the wild, they have to address them or be burdened with the bad word-of-mouth. With Windows, the users simply don't have that kind of overwhelming majority on their side.
Now, all of this wouldn't mean anything if Apple wasn't good at what they do, they could easily design a product and just abandon their users with it and all it's problems (see; Sony) - but Apple happens to be very, very good at using all the power that comes with a closed, controlled platform to the user's behalf.
So in my mind, it comes down to weather you pick a computer out like it's a "starter kit" - a jumping off point that with a just bit of work it returns vast rewards of unlimited potential and endless possibilities? - or - do you want a refined and finessed product that works as advertised right out of the box with very little hassle to the user?
In my mind, there's no wrong answer as long as you've asked yourself the right questions.
It all boils down to open-platforms and closed platforms;
A Windows PC is an open-platform computer which means the operating system, Windows, is designed with an open-ended approach to all the hardware, leaving much of the configuration to be done later, on a case by case basis. This allows for many manufacturers to create any individual components and anybody can assemble these components in almost any configuration, install Windows on it and you've got a standard user-experience computer... There are three main benefits that are exclusive to this dynamic;
1) an open, competitive, free-market of hardware manufacturers which helps drive innovation and keeps prices in check.
2) an abundance of configurations, models and options to choose from or the ability to custom build a personalized configuration.
3) a modular design which grants the ability to upgrade, expand, tweak and optimize throughout the life of the machine, as new technology comes available.
To a lot of technically-minded people, these three things are considered basic computer freedoms, like the inalienable rights of consumer technology.
From this perspective, a closed-platform system, like the Mac may seem fundamentally restrictive, backwards and even oppressive to it's users when compared to the 'openness' of the PC world... specifically in the three areas mentioned above:
1) there's no open-competetive market of manufacturers to help drive prices down.
2) At any given time, there's only about a dozen basic configurations of Macs being manufactured which pales in comparison to the thousands of PCs to choose from.
3) Macs are not "modular" and typically have very few upgrade options. They're designed and sold mostly as singular cohesive products.
However, the advantages of the Mac come specifically from this "closed-platform" approach. Advantages that come from running your operating system on the EXACT hardware that it was specifically designed for. Advantages like engineers being able to tweak and optimize the performance and configuration of every component from early on in the design process rather then leaving that responsibility to the user. Bugs and conflicts can be worked out on the assembly line rather then expecting 3rd party manufacturers or tech-support work out these details. By designing all the hardware together, in tandem with software it affords the ability to streamline and optimize efficiency from the ground up in a way that an open (or "hands-off") system just doesn't have the luxury of doing.
Additionally, because any Mac you buy is exactly like thousands of other Macs out there, it means Apple has to answer for each and every one. Being accountable means that they're concerned with the quality of materials and take great care to make their products live up to their brand name. When problems arise in the wild, they have to address them or be burdened with the bad word-of-mouth. With Windows, the users simply don't have that kind of overwhelming majority on their side.
Now, all of this wouldn't mean anything if Apple wasn't good at what they do, they could easily design a product and just abandon their users with it and all it's problems (see; Sony) - but Apple happens to be very, very good at using all the power that comes with a closed, controlled platform to the user's behalf.
So in my mind, it comes down to weather you pick a computer out like it's a "starter kit" - a jumping off point that with a just bit of work it returns vast rewards of unlimited potential and endless possibilities? - or - do you want a refined and finessed product that works as advertised right out of the box with very little hassle to the user?
In my mind, there's no wrong answer as long as you've asked yourself the right questions.