The layout your after is called the CSS 'Holy grail'. A list apart has a great article on it. http://www.alistapart.com/articles/holygrail
This one is good too. http://matthewjamestaylor.com/blog/perfect-3-column.htm
If you think the css in sitefinity is causing a problem, go grab the 'reset.css' from yui-grids and add it just before your custom css. It resets every css element back to a standard default value. (IE, Firefox, Safari, etc... all start with the same defaults.) You could use the yui-grids piece instead of the 960 grid system. Holler back if you would like to see a yui-grids example.
txyoji
2009-08-27 14:26:38