Don't forget futurama... It may be full of bad astronomy, but it does entertain. What other sci-fi (although not very sci) show, has an alien pet thing that excretes dark matter which is invaluable as interstellar spacecraft fuel.

Plus FOX has the greatest conspiracy theorist of all time on King of the Hill, Dale Gribble.

But I will agree that simpsons has lost it's zing, and with shows like American Idol, no wonder the rest of the world sees the US as sick and corrupt.