I've used black in baby quilts, especially with bright colors.
I heard that the more contrast, the more visually interesting for the baby; supposedly babies develop color awareness with black and white first, then the brights, then the pastels.
Those who received the baby quilts let me know later how much the babies loved the quilts, so make sure to put some good contrast in any quilt given to a baby (unless you are appealing to mom & dad :) )