How much page rank is decisive in ranking

We all know that page rank is an algorithm developed by google to provide the rankings about the quality of a webpage but how many of you think that page rank can be a more decisive factor in serp’s for those who don’t know about this short form (Search engine results pages).Many of us believe that if you have website with more sophisticated pr like above 4 or 5 then is quite sure that high pr site will rank better.

I have watched a lot of the websites which even though haing 0 pr are ranking well for a good competition better than a website with page rank but again it have some issues.If you have high page rank than even if you have single keyword in your index page your site will rank good for it i am talking about high pr not just 4,5.Even your insider pages get better rankings for it.