Getting a good PageRank for your homepage is important, but it is not the most important value for your site. Your Overall PageRank Power, a term coined by yours truly, is much more important than the PR of any given page. Your Overall PageRank Power is the total PageRank a page would get if it were linked to from every page on your site, and only from your site. Finding your Overall PageRank Power is fairly simple. Chances are you have a disclaimer or a privacy policy or something of that nature linked to from every page of your site, and these types of pages don't get links from outside sites. So to find your Overall PageRank Power you simply need to look at the PR of your privacy policy page or your disclaimer.

Overall PageRank Power is important and useful in a number of ways. For instance if you were buying a site knowing it's Overall PageRank Power, the total amount of weight it could contribute, would be very useful. If you were planning on building a complementary site to one of your current sites, knowing the Overall PageRank Power of the current site would like you know how much benefit you could get by cross-linking them. In that manner you could also use it to decide if you want to make a complementary site. For instance if you know the current #1 site on that topic has a PageRank of "5" and your Overall PageRank Power is a "6" then you can be confident that if you do make this site and cross-promote it with your current site then it will rank well.