Are they cheaper? Yes and no, putting your biases aside look at concrete facts. If your comparing a Mac to another OEM, then chances are they are about equal DEPENDING on the OEM. Most examples people have given are relatively poor, comparing the price of more mainstream and less quality manufacturers.
What I necessarily mean in a nutshell, you can compare a Mac and a Dell in price but your excluding a major factor of durability and overall quality.
For my examples, I am NOT going to give examples of computer manufacturers since I build my computers. You can build yourself a computer spec for spec to a Mac Pro, or an iMac of lesser cost, since I build my system and I know where to get quality components.
Continuing where I left off, not only quality components but also wire the interior to be clean and accessible.
As far as laptops go, they aren't over priced. Since DIY laptop kits are scarce your limited to OEM's. True, Mac's have a high resell value but PC's do have a good resell value as well, you just have to know what manufacturer to buy from. Thinkpads, and a lot of IBM/Lenovo models have a resell value equal to Mac's. I recently just sold my IBM T40 for $650.
Despite software you can compare IBM/Lenovo systems to a Mac, both are excellent quality. But then again Mac's have their own issues as well, which Apple isn't very fond of admitting. Where I work I've seen Mac's crash, drives failing, and components overheating just like any computer.
I am not being biased towards Mac's at all, I actually use them occasionally at work if I need to write something for the Mac platform. For the OS if you want to use it they're worth the price, but outside of work I wouldn't buy one. Not because I am cheap, it's because I have no particular use for the system. Also, to exclude your speculation I am nowhere near a Windows Fan Boy. At home I run Linux on my desktop and my laptops, and I've used it for a good 9 years.
Pretty much concluding myself, they're not necessarily overpriced systems excluding self built computers. Your paying for what you get, not just the system but technically a license to run the OS.