Sure, the Macs are expensive, but the hardware is very high quality, and when you compare them to Thinkpads and Vaios--other high-end computers--it's pretty reasonable.
I'm no Apple fanboy (as of now, the only money I've ever given Apple is 30% of app purchases I've made for my hand-me-down iPhone 2G), but in a couple of days, I'm buying a MacBook Pro because it's a high quality unix system that Just Works. Given that I'm a programmer who will use it constantly, the time it will save me should cover the extra few hundred dollars by the end of summer.
Most people don't compare Macs to equivalent systems, often because there is no comparable alternative. Even if you spec out a similar machine from other manufacturers you are almost guaranteed to be giving up something, whether that be battery life, a good case, or just the little touches that make you happy day to day like the battery life indicator or addictive multi-touch gestures.
Even the Vaio-Z, which is pretty slick and only 13", isn't on par with a MacBook Pro when it comes to the little touches. Yet it costs as much as a 15" MBP.
People who like to compare specs think they're getting a better deal but they rarely take into account actually using the thing for 8+ hours a day. The little things make a big difference when you use your computer that much.