I SO agree with this...
I had a 40D, and it had a usable ISO of 100...that's it!
I moved up to the 7D (and i do love it), but despite tons of advertising guff about high ISO, I maintain it has a usable ISO range of 100-400!
Even at ISO800, it is pretty poor, and getting up to ISO3200, it's all but useless...
Disagree completely. It's usable up to ISO 5000 in a pinch, if you have an image properly exposed without anything important in the shadows. Here's a shot I took at ISO 1600.
_MG_5647 by mornnb, on Flickr
IMAGE LINK: http://www.flickr.com/photos/mornnb/8332971653/
_MG_4315.jpg by mornnb, on Flickr
ISO 4000. I generally consider ISO 4000 the usable limit.
IMAGE LINK: http://www.flickr.com/photos/mornnb/7913023414/
_MG_2731 by mornnb, on Flickr
IMAGE LINK: http://www.flickr.com/photos/mornnb/7913012124/
_MG_2630 by mornnb, on Flickr