Tables suck if used for site layout. If correctly used then no tables can be used fine, just be sure to keep the styles in a CSS file and only use them sparingly to display tabular data. But their is other options mose of the time which work better to be honest.
Using table is OK but using DIV/css is better as DIV is manageable. No harm will be done with SEO campaign as it has nothing to do with SEO or ranking. It just helps to manage your site. eIDSeller
What matters is that you construct your sites so that search engine bots can easily crawl them. Poorly constructed tables can cause problems... which can hurt you if your site doesn't get crawled. This is why most advise to avoid them when possible.
Well, some people are telling that your source code should be smaller, so css layout would be better that one with tables... But people are telling lots of stuff..