2012 iMac --- i5 or i7 CPU, 21.5" or 27" screen?

I think that's what I'm going to do. I have an 08 24" iMac that's feeling pretty dated. I was intending to buy a new iMac when they came out but started looking at the mini. Looks like a better deal to me. I'm planning to buy a quad core i7 mini with fusion drive and then max out the ram with 2nd party memory. Haven't settled on the monitor but leaning towards a Dell U2410. Lack of discrete graphics on the new mini makes it a non-starter for hard core 3D gamers but the integrated Intel 4000 graphics controller seems to work pretty well for photo editing. It'll be less money than the base i5 27" iMac.