The first 200 words are critical. Put a text link to it at the TOP of your homepage. Additional text links to the sitemap in the navigation sections of your inside pages are fine. Submit it to search engines ONLY - not directories. The sitemap is your workhorse.
Many people report it's a high hit page.
Because it's content-laden, it may rank better then your homepage. It's also a considerate page for users who like to quickly get where they want to go inside your website. This is optional, and often necessary for huge websites that cover many areas, all on a related topic or are extremely competitive. Say, for example, your site is devoted to a band. Don't stray too far from that theme.