Depends on the niche you are in. For "myspace graphics" a fancy and flashy design is needed, while let's say for insurance you just need a professional website with easy to observe and use navigation with all the critical details easily observable.
From what everyone is saying: design matters. I wonder, though, because I came across this sales page and I hear it sells an enormous volume. Is it because he markets to people who already know his product? Or is it because in that niche, a design isn't necessary?
Meh, that looks like a typical ebook site. A lot of people like me will discount the contents without reading through because that's a typical ebook salespage.
the website design is just as important as having a good url, a good product, a good service, a good anything. To answer ur question of course web site design matters!!