CSS and SEO

Im not sure how much it really helps but I can’t see how it could hurt to try and build a page using full css for placement and style. This helps get all the extra code out of the document allowing your keyword density to be higher as well as your content to code ratio. This being said I still see a lot of terrible sites that show high rankings I wonder if this is because they have a lot of back links and have been around for a long time. Or it could be that search engines have gotten smart enough to not care about things like not using tables for anything other then tabular data. I am getting ready to launch 2 sites with very similar urls that will focus on some obscure keywords like "Samarian rock cutting devices in present day use" or "my roommate has 3 toes with pink toe nail polish on them" I am building both sites with the same key words and metatags also they have the same images and the same ip the only difference will be one letter in the url and one will be built in css and one using old style tables. On the table site I will use Bruce clay's table trick and on the other I will use pure css. I understand pure css doesn’t work for all types of designs due to browser compliance so I will make the design something that can work with pure css and work cross browser. This will allow me to test if using a css layout with all other factors being the same makes a difference. Each site will have 4 pages of content with each page having a minimum of four paragraphs and 3 images. i will then post them at the same time and on the same search engines and see what happens. Once I get the urls and the sites up I will post the addresses here.