Got mine last week, but one more to come
I got my home machine last week, a dual 2 GHz (ordered the day of the keynote)
It's very nice, and spends much of its time running at the quietest setting. It is kinda interesting to know when you're taxing it as the fans start spinning faster. For example, I was thinking about something and happened to have a text selection and was idly expanding and contracting it with the mouse. Slowly the fans spun up to a slightly higher speed. I stopped and said something like "oops, sorry...".
The machine is very fast. Some things you might expect to be CPU intensive, like UT2003, don't seem to tax it at all -- the fans mostly run at the lowest setting, or the next one above. I guess the graphics card is doing most of the work.
BUT, if you want hear how loud it *can* be, try running the Apple hardware diagnostics. It turns on all fans at full speed, and the machine sounds like a vacuum cleaner.
On the ordering/delevery front, I also ordered another one for work (ordered a few days after the keynote), and that one hasn't shown up yet, and just got pushed back to "On or before 10/29".
[I had thought it was 09/29 when I posted, but now I see it's 10/29.]