Good concept. Here are my suggestions: - Header images that are squared always look ugly to me. I would do the image as a background with rounded corners that extends from the beginning to the end of the site width. You can give it a fading style to the right side so the colors do not block the text/title. - The menu extension you have does not match the colors of the forum, it really stands out. Try removing the border, background color and change text color. Capitalize the M. Change the font color to Comic Sans and see how it looks.
nice work, it would be good if you try to make it wider ( 75px each side) and header banner is good but not attractive.