Umm..Just a couple of suggestions:
What about allowing the user to choose their preferred color-scheme? I have been to a couple of websites (can't think of one right this second) where when you sign up, you have your user preference and can select which color scheme you prefer. Give a couple of choices, and everyone will be happy! LOL also, that will allow for a change if a user is fed up with the colors and wants a fresh look.
Another suggestion, the advertising on the main page should not be THE FIRST thing we see when we log in, after a while I don't even notice if it is even there. Maybe move it down, along with the "sign up for the newsletter" part. You could put the ad space more in the body of the main page. The header should be dedicated to the logo and the name of the website, as well as sign-in boxes.
Which brings me to my next idea, to put the different related links directly under the logo/header, in form of tabs or buttons, so it looks more organized.