One of my best clients came to me this week with a large products page, and asked me to reduce the size (the number of characters in the HTML page) for him.
The page was full – it runs in a frame, and has a limit of 50,000 characters. They were already at 49,300 and had many more products to add.
I removed the table structure (a feat in itself! it was a nasty huge nested table) and implemented a lot more CSS, replacing the ubiquitous font tag and other similar elements.
My new page has 36,000 characters. I think that in itself is a pretty good argument for why tables are not a good idea for layout work.