Jeff, it seems Matt and Herb are on the party of noise reduction.
Again, no, I'm on the party of not caring if the image has a bit of grain, hence my tendency to increase ISO as the situations calls for. (And, with Canon sensors over the past few years, the small bit of grain experienced at higher ISOs hasn't impacted image quality to any significant degree in my images.) For California wide-angle photography, I'll often use 400 or 800 as the default...
I've never used noise reduction, either in camera or in post...stop putting words in our mouths, Drew
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Back to the regularly scheduled discussion: Interestingly, the old 20D had better dynamic range at ISO200 than ISO100, as it was clipping shadows to black in the latter. 100 ISO for every 10 ft might be a little extreme, if only due to the already variable exposure required for different angles towards the surface.