I don't know if it is the <li> that is the issue. The page that I am having the issue is http://www.mobile-home-sales.com/test/node.htm If you look at it in IE, it is the way I want it to look. In FF, the red area, the menu, has a large amount of space between itself and the left side of the column.
Solved. I had a floated image in the header that floated to the left. I just needed to clear the floats between the header and the content.