It is generally believed that the closer the content is to the top of the page, the better it is for SEO.  If that's incorrect, please let me know.

I have a 2 column site where the left menu is navigation and right side is content.  Obviously, the left menu appears in the code before the content does, but I can flip them around via css float.  If I do that, the content will appear on the left visually, even though in the code it still comes after the left side navigation.

Do either positions affect seo?