Hi, DP members: As an old member in DP, I have been as SEOer for a long time, but recently i have heard some one said that PR have nothing with your rank of keywords!
SERP ranking for any keyword is more affected by anchored keyword, backlink from relevant contents, dofollow value, aged domains, low outbound links. You can do a simple search on google with a set of random keywords, check top 10 sites and compare their top level domain PR and page's PR. PR have not effected SERP ranking.
Yes, Google PR effects SERP results but it is in fractions. So, no need to think about PR. Just concentrate on on-page, building good backlinks.