I've been a lurker on these forums for some time, but this thread inspired me to finally register so I could respond.
Some people are taking the internal appearance of the new Intel iMac (and the Rev. C G5 iMac) in far too a negative light. Since its inception, the iMac was never really intended to be a "user-servicable" machine, beyond installing an Airport card and additional memory. If you want a machine that you can dive into and adjust to your particular needs, Apple wants you to buy a PowerMac.
The latest generation iMac is essentially a laptop computer on its side. If you've ever taken apart a laptop, you'll know that they are not user friendly at all, aside from being able to add additional memory and maybe a few other things. I've completely disassembled a Titanium Powerbook as well as two late model iBooks and they require great patience and care to take apart and reassemble without damaging the machines.
Internal aesthetics of a machine that is not intended to be viewed by end users is less important than sound engineering practices that go into making the machine. It appears that the latest iterations of the iMac were redesigned internally to better facilitate cooling. This is a Good Thing, and means that your computer will be quieter and probably last longer if the internals are not roasting all the time. I doubt Apple engineers and managers sat around at a meeting one day and decided, "Hey, let's take our sleek iMac motherboard and turn it into a jumbled mess so users can't upgrade it as easily!"
From looking at the pictures, it's obvious that the switch to Intel processors had nothing to do with the latest internal iMac design since the motherboard and components layout appear similar to the Rev. C design. While there may be some legitimate gripes with regards to these new machines, it's my opinion that this is not one of them.
..Al