A lot of people don't like the design apparently. I've heard the word 'ugly' being tossed around quite a bit. I think it's the kind of design that you don't like at first but once you get your hands on one and really get to use and inspect it, the design makes perfect sense and you can't imagine it being any other way. The Ive interview gives a better idea of how well the aesthetics and function were married.
I think a lot of people were expecting something very 'sexy' as was the buzzword for describing Macs for a while. And they certainly were sexy. Who else but Mac users would use pictures of their computers as their desktops? But it was also this sort of aesthetic that made a lot of people scoff and decide not to take these machines too seriously.
The G5 is very serious.
It screams power. It looks like a forged tool. The exterior is almost purely function: aluminum for strength, thermal concerns, and an almost unibody construction; front and rear grilles for airflow; handles for transport. Nary a flourish in sight. In fact the only vain element you might say is the transparent door (so you can admire your computer while it works) except for the fact that it is functional as well (assists airflow).
I like this direction. I think Apple is saying "We've already established that we can make fancy computers. We can get attention. So now, let's pare down the form and get closer to the function. Let's make a computer that is startling in design at a glance but reveals it's beauty as we use it. That's where it should really shine."
The New G5: Speed Is Good, Ugly Is Bad