Neither.
In ancient days, people used tables for layout because it was the only thing that worked, but tables were never designed for layout and, now that there are better ways, using tables for layout is stupid (see article titled that under Howtos at the top of this page).
A <div> element is one used to provide structure to a page and group common elements together. It is never an automatic decision to use one anywhere unless it's necessary. Some pages can contain none at all.
Laying out a web page is done with CSS and the normal flow of all html elements on a page. The question of which to use, tables or divs, is not one worth asking.