Re: LeftCol bug remedies
I notice similar width measurement problems on my site when I was using PHP layers, I think its something to do with the way they define the container widths and inheritance.
See how the contents of your shoutbox wraps at the browser window width instead of its containing DIV's width? I found that dropping PHP Layers stopped this.
I managed to remove the extra few pixels width on my site by changing a width definition in the CSS from 100% to auto - this made sense at the time as the contents of the DIV in question were already at fixed or self-correcting sizes anyway.
Also avoiding the use of fixed and absolute positions in the CSS whenever possible tended to make the whole thing a bit easier to comprehend for poor old internet explorer, which has only learned how to render my top_bar template properly today.
It's always confusing when the borders of the page are rendered outside its viewable area, but the header (or is it the top_bar on your site?) expands to fill the space.