When it comes to SEO, there are three kinds of people. There are those that know little and do little; then there are those that know everything, they drill down into analytics and search results and can tell you where a page ranks on any given day. Somewhere in the middle is your ordinary everyday website owner who is trying to deliver the best program on a learn as you go basis. For these individuals, PageRank can still be a valuable tool.
It has been common practice in the blog world to seek out pages with high PageRanks and to then leave comments, hoping the pages use a dofollow.
PageRank can be useful for website owners within their own pages. If you know the PageRank for each page you can fine tune your SEO strategies for those pages. Internal links can be quite powerful if they are undertaken with care.
If you have several pages ranking fairly highly and another page that you want to see rank highly then internal links can help. Using standard SEO strategies such as good anchor text in the links you can funnel some of that PageRank into that page.
Whilst a high PageRank will not guarantee a high placement in the search results, there is little doubt that it does have some effect in the overall algorithm. Your SEO strategies need to use every option available to increase the rankings of each page. Knowing your PageRank and using it to effect is just one of those options.