I have had this same issue with many GeForce videocards on different monitors (not sure about ATI cards) - default colors are too bright, greys become glowing whites. I have to run "Nvidia Control Panel" and then set gamma, brightness and contrast all to 0. The brightness becomes as it should be but I am losing all greys and color shades.
In good old XP days I had default nvidia color settings and everything was fine. All issues started somewhere from XP SP2 or so.
Does anyone have any suggestions?