What is wrong with using HTML tables for layout?
HTML tables were originally intended to be used for presenting tabular data, not for layout. The W3C discourages the use of tables for layout because they are striving for a web in which content and structure are completely separate from presentation. In the W3C’s world view, CSS is the vehicle by which presentation and layout are defined. Browser support for CSS has improved significantly in recent versions, and growing numbers of sites are migrating over to CSS entirely for positioning.