I’m REALLY going to disagree with you on the Linux bit. I currently have state-of-the-art graphics cards on my system at work. I’m using them for some very experimental parallel processing which I can’t talk about unless you sign an NDA. Suffice it to say I can make them sit up and beg with the available drivers. My wife’s artwork is done entirely in FOSS graphics tools on her home Debian machine. For the average or even above-average user it works better than well enough. If you want Photoshop or InDesign in particular or are doing high-end pre-press stuff with proprietary Pantone combinations you’re out of luck. But even then, WINE is getting close to running those in Windows emulation.
For the other applications most people use – movies (viewing or making), vector drawing, painting, photo-editing and -sharing, and so on the alternatives really have come far enough that they are viable alternatives for most users.
And for the hundreds of dollars you save by neglecting the Microsoft tax you can get more RAM or a better card and make up the difference.
If you like Macs – and I’m personally indifferent to them – the cost is a little higher, although even then the difference isn’t as great as folks in Redmond would want you to believe. But the underlying OS is built on the most rock-solid base available, the OpenBSD and NetBSD kernels. Security is better. Benchmarks are excellent. Stability? There’s no comparison. Upgrades are a snap. Ease of use is vastly superior. Number of software titles? Not so great.
We don’t currently have a Mac except for the Hackintosh I built just because. But my 80 year old father has one. It gives him what he needs and more, and I don’t have to worry much about it. It just works. And that’s worth something.