I think most people wouldn't care whether it was a little thicker or had a chin, but when pushed would opt for the chin of the two. I can see it becoming less and less prominent as time goes on and screen sizes get bigger. This will make them more aesthetic for the living areas they are slowly migrating into. Would be nice if all iMacs from 24" upwards too also had ATSC tuners in them, (DVB-T in European models). Apple would be advised to also develop a remote that was as simple as the current one, but was touch screen and changed depending on function. Select TV and it refreshes to channel, volume and record functions. DVD gives play step, skip etc. Only works in Front Row, then defaults back to volume skip and menu buttons.
The Sony LA1 for example was very similar in design, a little thinner around the edges and thicker in the middle, but still not much more than the iMac. There was no foot and the screen was surrounded by transparent plastic which served little purpose other than standing it up. One major downside I saw with it though was the external power supply. Unless it's sitting on a desk with places to hide adapters, you're going to see a big black box near your machine.
All in all, the iMac still wins hands down in all-in-one design. I would prefer them not to refresh the look for the time being and maybe colours are all we need to satisfy us, along with added features and/or updated guts.