Off course both are equally important but if page rank is good for potential keywords than traffic will get increase automatically but if page rank is good and website not getting traffic or website get fake traffic than its meaningless, so traffic should be relevant and targeted.
Page rank is just a small part of Google's big puzzle in giving a good overall ranking to a site. Traffic makes you earn money. However, having concern on both factors is not bad. Just work naturally.
Pagerank is simply an indicator of the strength of inbound links... its a red herring. Focus on targetted relevant traffic everytime!
PR is an indicator of how valuable your page or pages are. That means the higher the PR the more people will likely keep on visiting your site.
BOtha re Important factors, if your website is more popular you will get more traffic from other websites, also you will get a high page rank ..Both are directly proportional to each other..Higher Traffic= Higher PR, Higher PR = More Links/popularity