For me, as a long time windows user, the value of a Mac goes beyond the cost of the components. OSX, the build quality of the machine, and the ownership experience add to the value of the machine IMO....this might not be the case for a lot of people...or even for most people, but if there wasn't a market for Apple's products at their current prices, which are usually quite a bit more expensive than similarily spec'd machines, Apple would not be enjoying the success they've had thus far.
For me the ability to run both OSX and Windows in tangent was a big plus for me. My Macbook pro will serve quite a few purposes. It will be my workhorse for grad school, my "leash" for work, and my workstation for photography jobs I do on the side. Both Windows and OSX have distinct advanteges for different uses. The ability to run both goes a long way....its literally like having two machines (at least the way I use it).
Ownership experience is important for me too. As a gadget freak, I've all sorts of electronic devices, and quite honestly, Apple is better to their customers than any device manufacturer I've had to deal with. When the button on my iPhone 4 stopped working, they flat out replaced it. They also fixed the screen on my wife's 3GS for free as a courtesy when she cracked it.
I've had several other devices break on me over the years....including a Samsung TV (3 months of hell to get it replaced), several HTC phones (lots of mailing devices back and forth, and not ever fixed correctly the first time), and an Onkyo receiver that I currently have in the shop (no home theater at home for the past 3 weeks and counting!) because an HDMI board fried...which is apparently a common problem for their receivers.
Without being pretentious, to me the difference between a Mac and a PC is like the difference between a Toyota and a Lexus. At their core they may share the same components and be built from the same platform, but the fit and finish on the Lexus will be quite a bit better. Plus Lexus will give you free oil changes and car washes, a loaner car when you bring it in for service, and will all around appreciate you more as a customer