And the overall of this posts are:
You want slimmer
You want quad core
If it's slimmer it doesn't have space for quad core...ever tought about the quad cores even smaller..hann!? it wouldn't take so much space lololol
And if it's quad core, you say that the most people that use iMac's doesn't use the full potential of the iMac.
Ok, so where do we go from here?
Personally i would prefer quad core to being slimmer, i'm in the graphic design / movie editing business, it would be great to have a powerfull machine to take all the action that i need in Premiere, and making full size print jobs, and to have a lot...a lot of files open at the same time. But, if it slimmer i don't say no, my desktop is always a mess full of papers pen's pencil's the iphone a tablet, cup's...my god, if i hade something more elegant on top of it it would look nicer..or not lololol. So i say, quad core GO!!
Unless good ol' uncle Steve would devide the iMac line in, thinner + dual core and normal size + quad core...that would make sense, wouldn' it?