Let me take an example to explain my situation:
I have a site on widgets called mysite.com
I have created different pages like: /overview, /news, /forum, /blog and /classifieds etc.
I understand what keywords to target for each of the sub-pages, example, target "widget news" for /news pages similarly, I am targeting "widgets" for my /overview pages.
I am confused as to what keywords to target on our home page which has a summary of the entire website.
Should I go ahead and again use "widgets" as the primary keyword on the home page as well. Would it not compete with the /overview pages on rankings.