PR is a nice to have and worth striving for as it shows trust and ranking. However, it is not everything, some bloggers have done very well by having quality blogs that have strong content that appeals to readers, but perhaps not to the search engines.
It's also important to note that pagerank (for a given page on your site) is not the endgame of your goal: getting quality visitors to your site. It is one of many indicators of Google's way of ranking that particular page (based on many factors, including inbound links and their rank) in relation to its peers on the web. Focus on the end users... not the search engines! Rob
It was and will stay one of the most important factors to rank pages within Google SE, check this out: http://www.google.com/technology
Google basically runs an algorithm through the whole web. Each web page is assigned a value based on the amount and PR of pages that link to that page. The algorithm is changed periodically and updated constantly. The higher the number the better your page ranks.