I've been in the market for a new iMac to replace my slow mid-2007 model since late last year. I figured the new ones were just around the corner. They didn't appear in January. Researching it, I realized they were probably linked to Intel's release schedule. But they didn't come out with the new chips. When they were finally announced, the 27-incher that I wanted was still vapor, not coming until "December."
That did it.
I ordered a 27-inch Dell display that got a great review at AnandTech and a maxed out Mac mini with a Fusion Drive. The display is in the box here and the mini has just left China.
On the graphics: I read the tests at BareFeats.com that people are talking about, and then I downloaded the two utilities they used (Cinebench and Unigine-Heaven) and tested my iMac's graphics myself. My iMac rates 1/10 and 1/6, respectively, for CPU and OpenGL speed of the Mac mini tested, a 2.3 quad (I myself splurged for the 2.6). So the mini should scream compared to my old iMac. And graphics is not my choke point on my current machine. CPU speed is. So I'm not too worried yet about the lack of a discrete graphics card.
Remember: the graphics mostly affects game rendering (I don't do games) and rendering of edited video and 3D models, as well as Photoshop filters on large images. I use Photoshop, but only basic filtering on web-resolution images. For interface element rendering I don't think there will be any problem at all on even a 27-inch display at maximum resolution. We'll see though: as I said I don't have it yet.
I think the iMacs are getting more and more crippled, CD slot aside: for instance, the Mac mini has an Audio In and an Audio Out. The iMacs have only an Audio Out (which they renamed "Headphones" so as not to emphasize the lack of in/out symmetry). I wish they'd make the iMac _thicker_ and the mini _taller_ and just put all the stuff in them that is needed, without compromises.
I'm starting to feel that us desktop guys are going to see slimmer and slimmer pickings from Apple, and I don't like the dumbing down of OS X either. I don't like all the iTunes updates for features I don't want, I don't like iCloud, and so on. Now that I have a more componentized system with the mini, I plan to buy a KVM switch and a small PC box and load Linux on it and reacquaint myself with it, looking to become a possible future "switcher" if I can get my work done in one of the Linux distros.