I had seen something about the iMac's price being reduced in Computer World so I headed on over to the online Apple store and went through the motions to add a top of the line 27" iMac to my cart and got a wake up call. Just three years ago I was able to purchase a 27" iMac with best GPU available for $1,900. on Amazon.com with no sales tax. That was the train I got on. Just three short years later to buy an iMac with the best GPU I have to go BTO and to get a system suitable for gaming and with hopefully some longevity (but it will be limited by the mobile GPU just the same) it is now around $3,500. with local sales tax.
Here are the options I looked at from the new 27" and 21.5" models to the current Mini and 13" Macbook Air which I might consider where gaming isn't going to be a concern anymore most likely and being able to use it while relaxing on the living room couch would be nice. The speed would be nice too with an SSD. Without all the games, I don't need nearly so much storage for the stuff I keep.
Here's the four systems as I'd configure them for my purposes if I were buying today but I would not buy the 27" iMac. For a gamer, it just isn't worth it at all. So really I would just be considering the other three options for all things OS X and something else entirely for most all gaming.
This will take you to a Flickr album of Apple Store cart screenshots showing configurations and total cost with local tax here:
If you click on one pic, you can then page through the five of them. I include a ASUS monitor I'd buy in the case of a Mac Mini which in total with that monitor is the cheapest option. The Macbook Air has mobility and speed going for it. The 21" iMac is hard to justify. The 27" iMac is ridiculously expensive. So for me, either the Mini or the Air would be chosen if I was buying a Mac today.
Honestly, the expense of this stuff is enough to make me think about just getting an Air for computing and a console for gaming.