Well to be fair, it's also wider than I generally keep my browser window at (around 900 pixels on a 1280x1024 screen - our forums default to 800 pixels).
Anyway, even if you assume everyone has at least 1024 resolution and the window maximized, you still have the width of the vertical scrollbar to account for, so at least make it around 1000 px wide maximum if not narrower. If it could be cropped and shrunk down to about 760 that would be best.