I see that there are a hundred questions here on meta about the color scheme, but this one is very specific and easy to fix:
stackoverflow.com has colored links for each of the main navigation buttons (Questions, Tags, Users, etc.). The text starts out white. In IE6 (horrors!) after the link is visited, it turns a kind of teal color. The "visited" teal colored text on the gray background is very difficult to read. Can the page styling be fixed so that the link color does not change when visited (text remains white), or it changes to another bright color that contrasts better with the gray? (Off-white? Lighter gray?) When I test it out on Firefox, the color scheme of the link doesn't change after it's visited. The same complaint can be made about this site (MSO), but the visited link color is burgundy instead of teal.