This is one of those web developer theology questions that can usually cause quite a stir.  Some people will say that tables are completely unecessary with modern css and will make great efforts to replace tables just for the sake of replacing the tables.  I tend to believe that everything that can be done with tables can be done with divs, but sometimes, forcing it seems like overkill.  One thing tables do very well that is tougher with divs is multiple columns of data that all have to be the same height.  If you place two divs side by side and need them both to be as tall as the column with the most content, it can be a real pain, especially cross platform.  In the end, there is no real reason to hate on tables, but they should be used with care.  I've seen some sites go off the deep end with tables within tables within tables (etc).  If you are doing that, you can probably simplifly the markup.