I really haven't much to add. Mac and Windows monitors have always used different gamma settings, so cross-platform there is always some difficulties. But you've just changed from OS9 tp OSX, and you've changed from a CRT to an LCD? It sounds like you are doing the right things to isolate the problem; checking out old scans on the new setup. As I remember, when installing the Nikon software it has you pick between a couple choices for color space? I'd not be surprised if there was somec incompatability between the Nikon software and the state-of-art Mac drivers. VueScan does claim to be able to use the infrared channel for noise reduction: "Infrared clean Use this option to remove dust spots and scratches. It's only available when an infrared channel is available. This option only causes image softening in the immediate vicinity of dust spots and scratches. You can control the amount of cleaning of the image by choosing the Light, Medium or Heavy options."