The XTi produces images with beautiful, accurate colors
as we should expect from any modern digital slr. Initially,
using the "Standard" Picture Style, I found the colors a little
muted, and bland, but overall accurate.
Your lens selection may help with colors from the XTi. The image
above was taken with the superb Canon 70-200mm f/2.8L IS zoom, and shows
beautiful, subtle gradations of yellow-orange in the taxis. The yellow
cab is a true icon of New York City. A nice gamut of colors also can be
seen, from the black gates to the different colored shirts of the pedestrians.
This image is from my first hours with the XTi. I used the "Standard" picture
setting, and did not bump up the color saturation at all.