In many webmasters opinions it really depends on your own ethics and needs as well as your purpose for the site overall. Many webmasters don't buy or sell links, because according to them it is unnecessary. Some webmasters believe in their own capabilities to be linked to by others.

PR matters quite a lot, and here is why. When you search for the most competitive terms and only the ones with good PR turn up in SERP's first page. PR also matters when you want reputation as a site not only in SERP rankings, but with your visitors and fellow webmasters as well. PR matters in terms of trust as well, a visitor who has even the slightest idea of PR will know the difference between a site with PR and one without. Does it mean that a site without PR or one just starting up doesn't have that capability? It definitely has the capability. Every site starts from the pit, the very bottom where the PR is non existent. Building trust by writing and including "quality" content will help even if you do not have a PR. Imagine if your site had PR and quality content! Even if you don't rank well in the search engine, the people who visit your site will know its importance in terms of Google's opinion to it all, after all PR is Google's opinion of your site.

Some say, backlinks are everything, this is wrong. Backlinks are only part of the PR assessment. It is very possible to achieve as good a PR as a site with 50 backlinks or more just by making sure your backlinks are high in quality and diversity. Quality does not always equal quantity when it comes to PR.

Can PR affect SERP rankings? Yes, of course. For example, if you search for the term "computer" and check the PR of the sites of the first few listings, they will have good PR. If you look again you will see that some of the sites with higher PR will rank lower in the search engine. Why is this? PR is given to you after a certain period of time, search engine rankings are more dynamic and the "whole pie" of the the ranking is not entirely based on PR. Search engine ranking is based on number of links, people visiting and talking about the links, the diversity of the links, and the authority of the links as a whole. SERP positions can vary everyday, every hour but PR varies only after a certain period of time. Most webmasters agree that SERP is determined by much more complex things than PR, but PR is a big factor in its determination. The difference in terms of position is merely between a page, meaning, if the lower PR site is at number one then the higher PR site is there within the first page. In the long term without quality contents, that lower PR site will surely fall. The factor of time depends on the niche itself, some niches get new content every second and some every week, therefore the niche you are in really does matter.

Those who say PR is only good for link selling are not paying attention. There are enough non profit organizations, bloggers and personal sites out there which prove that wrong. Link buying/selling just for PR is just not good, on the other hand if you are buying/selling links to build traffic then that is a whole different issue.

PR is very useful for ranking well in the SERP, searching for the term of computer proves that. For example, Dell's PR is 8/10 and Apple's PR is 9/10. Why exactly is Dell is up there over Apple in the rankings? Here is why, it is a general fact that Dell is much more popular to people that Apple is, so Dell ranks better. The next question is why doesn't Google present Dell with Apple's PR or better? In terms of web (internet) development

Apple is much more relevant than Dell which puts it at PR 9. In the world's economy quality is not always first, sometimes we compromise quality if it is of a lesser price and easier to implement and that is the case with rankings. PR is the value and ranking is the popularity of a site as a whole. Blackhatters can manipulate the rankings big time but never for the long term! Google is supreme and at the end of the day Google's search engine is user friendly, not webmaster friendly and that is the way it should be. Google realizes that not everybody on the web is a webmaster, normal everyday people need to be able to find what they want, and that is the way we should want it.