It is advisable to use tables in HTML pages (now that we have CSS)?
What are the applications of tables? What features/abilities does tables have that are not in CSS?
My very simple and basic opinion on this is that tables are there for tabular data - not for positioning one thing on top or next to another element because you happen to like it being there.
So - if you want to display a table of data: do so (with a table). If you want to position content on the page: use css.
Reserving tables for use only for tabular data works most of the time. There are certain layout problems that are much easier to achieve with tables than anything else. For example, vertical alignment and equal height columns. On the other side of the fence, there have been some complex data tables that I've used floated divs for because tables weren't fitting the bill.
Like anything else, use the right tool for the right job, and sometimes the most pragmatic tool isn't what you think it would be. That said, I rarely use tables for layout, even in the examples I gave, because inevitably I hit some problem that makes me have to do it with CSS anyway. Your mileage may vary.
Tables are used for displaying tabular data. There's not much else to add :-D