There's lots of questions on this forum (and others) about link building, what types of links are good and what types of links are bad.
And...you will see responses to these questions like:
"0
PR - no good"
"Low
PR - no good"
"Just build more incoming links!"
But these answers are narrow minded. What you need to do is build incoming links that are relative to your site/blog and bring visitors that stick around to read other pages on your site, purchase something, bookmark you, recommend you, or link to you without being asked. These all are beneficial to your business.
Sage Lewis, of Search Engine Watch, has posted
All Links Are Not Created Equal which shows that
PR and traffic from certain sites isn't as beneficial as you might be lead to believe.
Have you conducted the same experiment? What are your findings?