Many search engine marketers think who you link out to (and who links to you) helps determine a topical community of sites in any field or a hub of authority. Quite simply, you want to be in that hub, at the centre if possible (however unlikely), but at least in it. I like to think of this one as a good thing to remember in the future as search engines get even better at determining topical relevancy of pages, but I have never actually seen any granular ranking benefit (for the page in question) from linking out.
Sometimes we refer to those root keywords as "vanity keywords," because if you do just one search to see who seems to be winning the space, you are likely to pick the single broadest keyword and see who comes up ranked highly. In nearly every case, however, we have found it to be more successful and deliver a significantly better return on your SEM investment by focusing on the hundreds or even thousands of more specific keywords that more closely match the services, products, brands, and locations that you sell or serve.