[Rickster]

Here you go ... let's compare apples to apples ...

800
Image removed

1600
Image removed

3200
Image removed

Which images above have the least noise and highest detail?

Although the color balance on the 40D images are a bit more pleasant they are not accurate. The whites are beige. RGB values for white on the 40D = [239,228,212] vs [250,250,250] for the K20D

According to the EXIF data, the 40D images were shot in AUTO WB and the K20D images were manual. I don't think we can say much about WB in these images except the K20D manual WB balance appears to be spot on.