A bit too late but just in case…
On my experience I found out that with or without table doesn’t make much of a difference in SEO results.
Content and popularity is what really matters.
In 2004 I did change gamblerplace.com from table to tableless… huge amount of work… didn’t change anything else and boom… nothing different happened.
What seems to make a difference like many said, it is to make the html as simple as possible using CSS. If Google have to spy a page with 50k of pure messy html (table or tableless) and another with 5k and similar content, I’m sure that will count something against the first one. 10 times more html for the same content in 10 mil pages makes a good difference.
Another thing that I’m sure counts for something is invalid html tag. If you say that will provide xhtml tags and then your pages have lots of opened tags (ie [HTML]
[/HTML] where should be [HTML]
[/HTML]), for me sounds like creating problem on simple things.
Old school and interesting facts:
xxxhttp://www.websiteoptimization.com/services/analyze/
Again, as long as the html is somewhat clean and your site is popular, you should be good.