A lot of people say about the page rank of a website is no longer important. And yes doesn’t affect SERP positions. But if the pagerank measure the importance of your blog, is not important to have a “important” website.
The page rank is not important for guys who make money only from adsense. But if you want to sell advertorials and make money selling banners directly is more easier to go to possible clients and show your page rank and traffic data.
You don’t need to be a maniac and try to have the biggest PR in the word, but have an eye to this, too.