I don't have to spend my time on setup/programming/misc computer-related stuff. My time is valuable. Running a Mac, I needn't spend time thinking about (and acting on) things like buying and installing graphics hardware, doing software set-ups, writing my own scripts (been there done that), viruses and worms (never had one), setting up and running security software (firewall is automatic with OS; anti-virus not needed), blue screens of death, patches, cascading pop-ups, indecipherable error messages, dll files, OS reboots (I've run OSX approx 16 months - to date: 2 hangs, 0 crashes), etc., etc. In the Mac world, these problematic things just generally don't happen
I don't have to deal with Microsoft's annoying personality traits and user abuse. Do I pay (in Mac inflexibility) vs Windows or Linux? Certainly vs Linux I do; my geeky friends keep trying to sell me Linux' flexibility - I tell them I haven't time to learn and do everything myself. ...vs Windows, I'm not so sure. I used W2002 Pro for about 6 months last year on a contract project. While it had a few features that would be nice to transfer to Mac, for the most part I found the new Windows to be cranky, inflexible (eg cleaning the crap off the desktop is not allowed), much slower than Mac in some functions (eg bootup)despite faster hardware, tediously complicated, and as non-intuitive as ever.
The flip side of Mac's inflexibility is that, once you know Mac, almost everything you need in daily life is very fast and smooth, and the learning curve for everything related to it is short and shallow.
Conclusion (for me, that is, ymmv): a few extra bucks spent on hardware at the front end is well worth the time and money saved over the duration. It's about total cost of ownership.
I also visited here: http://iscs.us/xvsxp/ and found my weighted preferences gave OSX an even larger differential (~1.17 v ~1.12) over XP Pro (who would bother with "Home Edition"?) than the "final-score" unweighted differential. To each his own, of course, and the results reported by these sites are obviously subject to the biases of those who built them.