I definitly think content is the most important factor in google rank right now.
I own some websites and I tried many SEO tecniques, but I saw that any SEO tecnique is useless without a good content. So IMHO a great content is the most important factor, and I don't meant only a long content, but also a not-copied, unique, grammatically correct and well wrote content.
Then comes other things like backlinks, meta tags, keyword density optimization, LSI optimization, article marketing etc...
That's my 2 cents