Recently I was looking for a simple html editor that had a design mode and source mode and did not change the original html that was suitable for business users. Sounds simple right, wrong. My first thought was Windows Live Writer, but I found it does in fact change the html; body->tbody which is not valid by Constant Contact (html was used for emails).
After going through many different free editors I finally found one I liked, and it is integrated into a browser. The one I found is part of the SeaMonkey browser. After installing SeaMonkey go to Window->Composer and you will find a nice html editor.