First of all, separating presentation and content makes it easy to edit websites.
Using tables for layout and fiddling with rows, columns and cells for page structure is counder-productive. Simply using CSS make sthe site much more easier to edit.
CSS can and is used to position elements on websites. Have you checked
http://www.ESPN.com? They are on CSS, and have been for three years.
As for bandwidth.
True, bandwidth may not be the issue today. But page size may be viewed from another side of the fence - your visitors.
A site on CSS is twice as smaller than a site on tables. Of course, the amount of images may delute the advantage, but on a site with 140kb of images, total page size decreased by 10% after just redesigning with CSS. More (20-30%) could be achieved with optimizing the images, too.
Think of it this way: CSS is another tool to increase site download speed and to make the site easy to edit. And it is proven.