I think all search engines are members of the W3C and I believe they will place a site written in standards above a site that is not with all things being equal. I have never failed to put a site in the top 10 that had valid code. That has just been my observation. On one key phrase affordable seo company oregon I have #1 #2 #3 #4 #5 #10 even though there is hardly any competition. On affordable web design company (yahoo) I have been #1 for 14 months with valid code. And on google I have a #1 with a PR2 ahead of a PR6 because I have valid code and he does not. I have notice this several times with not just myself but with other designers that use web standards.
We all have our own ideas which is great and that is why I joined this forum. I will learn something from others if I take part in the discussions and hopefully I have some knowledge to pass on to others.