Well, I bought my MacBook Pro 17" last year because it was lighter and thinner than my previous comparably equipped Dell, had a longer battery life, and had a much more reliable and speedy OS than the Dell. Is a "good" OS worth several hundred extra dollars? To me, you bet. For me, the price premium is justified simply because I don't have to wait a minute for the machine to wake up from sleep every time I lug it from home to the office or vice versa, or when I come back from lunch. Not having to reboot at least once a week (usually much more often) is also worth some of that cost. And I didn't have to spend hours of my life digging into obscure settings and learning how to set everything just right to make that happen. Also, on my Dell laptop, I often found that I'd be in the middle of typing, in a browser or on the word processor, and some other high priority task would kick in for unknown reasons, and what I typed wouldn't be displayed for several seconds. That hasn't happened with the Mac. Also worth a good chunk of money to me.
As for your Linux PC, please. As another responder noted, Lightroom is THE easiest to use, most powerful photo-editing and photo-organizing software out there. Photography is my major hobby, and switching to Lightroom has drastically reduced the time it takes me to sort, select, and edit my photos. That caliber of software is not available on Linux at the current time.
So thank you, I think my choice of the MacBook Pro was quite rationale given my needs and what's currently available on the market. A pretty case had very, very little to do with it. If Dell or somebody else could make a Windows machine function this well, I can assure you I'd be happy to buy it... and then there would be real competition, and Apple would have to lower its prices some and no longer make more money per PC than anybody else. Apple decided to compete on performance... REAL performance, not tech spec porn performance... and it's winning, and thus making more money.