Sarge,
I built my system for $700. It has a six core processor, 4 GB ram, a 360 GB hard drive, a 22X dvd /rw and a decent motherboard. (Gigabyte) The only things I may even consider upgrading are the video card (currently onboard video, which isn't too shabby in itself), the sound card (that's questionable, but I really DO like Creative products), and add in an SD card reader. With W7(64 bit), I have had ZERO problems other than some program compatibility. The CLOSEST that mac has to mine is with an Intel i5,(quad core) which pales in comparison to my AMD PhenomII X6. And........ if I add in the previously purchased monitor, (20" widescreen), it may add up to $850. That's being generous. The closest I can come in price is double what I paid for my system. ($1700) That doesn't include any tax or shipping from apple. (I was wrong with my earlier estimate, so sue me) Since I run on an UPS, my computers have been quite stable.
That said, like I stated earlier, hardware is hardware. (the hardware specs for my system are the same, if not better than the apple system). My system has much more flexibility, too. The macs aren't much different, internally, than a PC. So, what one is really paying for is the OS.