So if you haven't heard about the "Our Leader" billboard, read this. While I agree it's kind of goofy and reminiscent of dictatorships, it's not like Bush himself put up the billboard, or used state money to do so. It's just free speech in action, so really, I think people are making a mountain out of a molehill.
Besides, people can just use their free speech to make other billboards, like this one that's further down the road:
If you don't recognize the photo on the left, look here.