Yup, you need those landing pages believe it or not. And no, these are not the landing pages you created specifically so that you can capture an email adress when someone clicks your Google PPC ads.
There is more to it now than that, especially for SEO, which means better organic rankings.
According to Sam Niccolls of SEOmozBlog, many businesses, even established ones, still think their only way to organic listings is through the homepage.