@fcwestfall (Fake Chuck Westfall) pointed us to this review of the Canon EOS 7D's noise in comparison to the Canon 40D.
There are plenty of still samples and they make a good comparison. Obviously, I've not made this comparison myself, so we'll just go with his opinions.
“And many of the people that couldnâ€™t wait to buy the 7D are now experiencing exactly what I meant when I warned not to become Canonâ€™s beta tester. Canon has so far had to release TWO firmware updates for the 7D in the very short time period of just one month that the 7D has been available. The first update (version 1.0.9) was to correct autofocus problems in Live View mode, and the second update (version 1.1.0) which was released a few days ago, was to correct a ghosting problem in images (Fake Chuck Westfall has more on this here). In addition to this, many people are experiencing autofocus problems with their 7D cameras. ”
So, please go read the review on Karel Donk's site.
(Photo credit: snap from canon)