Great post. Just a quick note to add that
SEO does not reflect in your site's SERP position immediately. It takes some time. Also
SEO is an ongoing process especially for the more competitive niches
But you are absolutely right. One of my sites gets about 1000 uniques per day from the search engines. Now to some that may not seem like much but if you think about how much i would have to spend on PPC to get the same number of visitors, well it speaks for itself