The top is a picture of a Gretag-Macbeth (now X-rite) color checker chart taken with a 5D, and converted with Adobe Camera Raw, using the default profile. The bottom is a digital representation of the chart that I found somewhere on the web. The only processing I did to the top image was to white balance using one of the gray squares, and to then adjust brightness and contrast until the white and black squares matched the target values reasonably well. This seems to show that the default ACR profile makes reds too bright. Otherwise, the colors are pretty good. I haven't decided yet whether it's worth trying to come up with my own profile, e.g. as described in the following tutorial.