Just get the links to the most relevent page on your site. A simple way to do this is to look at the page title of the page you are getting the link from and then ask yourself what page on your site matches that the closest.
It is tempting to get all of your backlinks to your main page in the hope of getting a high
PR, but from my experience this is not a good idea.
There is an article here on deep linking and how to calculate the ratio etc... :
http://deanhunt.com/time-to-go-deep-linking/