Obvisoully the reason why someone is coming to your website is to gain knowledge from the content in which you are presenting them, so the content itself is very important and how you present it, as for design, its important to have something that is easy illy accessible but at the same time still catches the eye. I also find it niche specific too, for example if your running a design website or blog ect.. then you may want to focus alot on the design aswell as the content.