You will often read that getting backlinks from sites with high PR is far better than from sites with a low PR. There is some truth to that philosophy, but it is not the whole story.
First, links are links no matter which way you look at. 100 links from a PR 1 or PR 2 are just as good as 3 or 4 links from a PR5 6 or 7. However, what many people don’t realize is that the web is an ever growing and ever evolving entity. Those 100 links from PR 1 or 2 sites will over time change their PR value (if PR retains it’s existence).
Of those 100 sites, you don’t know what their future holds. you could end up with half of them being in the 4,5,6 or 7 range is four or five years time. It may not help you rank highly today, but in a couple of years they could be make a huge difference.
Some smart SEO operators are now seeking sites, particularly blogs, that are on the move. They are looking at quality, frequency of posting, and trying to gauge the personality behind the blog – that is, are they are stayer. It is not that difficult to find a dozen or sites that fit within your niche, are of reasonably good quality, and look being around for the long term.
Find those blogs (or web sites) and foster some interaction to gain links and over time you may find that as they start to rank higher, your pages will as well.
Yes, for quick results, the higher the PR the more valuable those links are. However, if you put yourself in their shoes, the higher the PR, the more you want to protect it and the less likely you are to be linking out willy nilly. Sites with a lower PR will often link out more readily if you approach them in the right manner. As with most things SEO related, time is your best friend – don’t always try to rush things.