While the web design community gradually moves away from using tables to lay out the structure of a page, tables really do have a vital use, their original use; they're for laying out tabular data. For instance, imagine a table of employees. Pretty simple. But if you saw that table in a client-side application, you'd expect to be able to click on the headers and have the table sort, would you not? I know it always annoys me when you can't.