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I totally agree with people that say it depends on the scene, shadows and usage of the photo, especially at ISO's 1600 and greater.
No not really, it depends on your exposure, and the DR of the scene. If you underexpose the 7D at higher ISOs by a stop or more, and you bring them up, you will really increase the noticeability of noise. You have to push your exposure to the right without clipping to get the best out of the 7D. I can take the same scene with shadows and all, and show that if you expose where the histogram lies in the middle or to the left, then again where you push all that to the right without clipping highlights, there is a very noticeable difference in IQ. ETTR is nothing new, but is especially important with these 18mpx croppers.
Here is a shot from the 7D in a low light situation, natural light and nothing more. I had set up the camera in a way to try to get an okay SOOC JPG, but then I also took the raw, changed a few things around, and ran the resulting JPG through one of my custom actions. It comes out better, and this is why I only shoot raw now, and I keep the exposure to the right at all times. This allows poster prints of players at ISO 6400.
Now if I print either image at 8x10 or maybe even a larger size, will there be a discernible difference? Yes, maybe if you really start to scrutinize the image, but for the most part, the technique I employ may not always produce great differences that everyone can appreciate. I just like having a process both when I shoot, and when I go home to process so that I don't have alot of work or have to think too much about each image.
SOOC JPG at ISO 6400
100% crop of SOOC JPG
Raw of same image, tweaked, then processed in CS3
100% crop of raw->jpg image