If I'm going dark, I've always defaulted to black. Right now, I'm planning a Storm at Sea quilt (entitled It Was a Dark and Stormy Night at Sea) that will use a black background. However, for the next one I may try navy. I've never considered navy before, and I can see where it would be quite striking too.
Oh yes! I agree, black really does make bright colors "pop". If I want a more traditional, old-fashioned look (which I love also), then I go with white or off-white.
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