When I was building my PC, I compared buying the parts in a few of the alienwares and actually buying the alienware. The alienware was always more expensive, but only by a couple hundred or so. If you want the name, alienware isn't as bad as I thought it would be. Having said that 200$ can be the difference of having a CPU or not.
Like everyone else has said you buy a Mac so that you can say you have a Mac. I really enjoyed building my computer, especially when it turned on and I knew I had done something right. Building takes more time, but you get more out of it.
Instead of buying a $3000 Mac, buy your wife a nice HP or Dell (I recommend Dell, they seem to be more durable than HP based off of personal experience) for $1000, and then build yourself a $1500 PC. With the extra money buy this monitor -
http://www.newegg.com/Product/Produc...-313-_-Product. I have it and I LOVE it.
When it's all said and done you walk away with two very nice machines, both of which outclass a Mac that would have been 2-3 times more expensive.