page rank is the very core of google and the formula which allows them to assign a numerical value denoting importance to a page (all pages online). it is a separate function from returning results for search queries.
what you rank for is determined by the competition for that phrase and how you are targeting that phrase + back links etc etc etc.
everyone loves to say they rank well for a phrase with a low PR site.. well, that's not possible if you have a high pr site targeting that specific phrase. for example, if naughty.com creates a page to target a certain phrase, links that page internally and externally and makes it a pr4 - which corresponds to an actual page rank value (scaled from the actual page rank values of all sites online) - you aren't going to beat them.
its not a short conversation. and its not possible to discuss without over simplifying things. but in general, the answers you are going to receive to this question are going to be very misinformed and misguided.
PR does matter - because it is a true number which represents a value assigned to a page determining its importance and is a value, some of which is passed to other pages via linking.
PR does not determine what phrases you will rank for
What those who rank for the phrase are doing is going to dictate where you fall in the SERPs as much as what you are doing.
It's like having a machine gun. I can give the average GFY webmaster an M4 Carbine and turn him loose in the forest... i can give a marine scout sniper a bow and arrow to hunt him down... the webmaster has little to no chance of survival... and in the end, its about everything else that determines how you use those weapons effectively.. not that you have them or not.
