its ok to use tables when you are showing data in a grid / tabular format. however, for general structure of the site, its highly recommended that you use css driven div, ul, li elements to give you more lucid website.
If you anyways decide to work with tables, you must consider the following cons :
- they are not SEO friendly
- they are quite rigid in terms of their structure and at times difficult to maintain as well
you may be spending little extra time on div based website, but its worth every minute spent.
