sorry to hijack but comparing the 5D and its possible replacement next yr, how does the IQ compares to the 1D Mk III. Let's say shooting portraits.
By all current reports, high ISO noise is comprable. Colours are truer on the MkIII, but tones are smoother on the 5D. Unless you're doing massive enlargements there will be a bigger e=impact from post processing then the output from the individual cameras.