Pure logic should dictate that unless we have more info, we should assume that PR amounts to less than 1%, since there are "more than 100 different factors".

While most of us have a "hunch" PR is more important than 1%, we still need to consider that there are more than 100 other factors which should help keep PR in perspective.

One thing is certain, there is NOT a direct correlation between PR and ranking. If this was true, you'd see the highest ranked pages always have the highest PR, which just isn't the case.

Below is the results for a "PageRank" search for search engine marketing, with the PR returned for each results:
http://www.seochat.com/?tool=7&option=com_seotools&hl=en&lr=&ie=UTF-8&oe=UTF-8&q=search engine marketing&result_mode=relevance&num=100

Note that PR is returned for each site in the SERP.

I used search engine marketing so we can assume each site has done some basic SEO so we can more easily seperate the impact of PR.

As we can see, having a good PR seems to be helpful, but I can see a PR 4 site outranking PR 6, 7 and even 8's. While the PR in the Google bar isn't always up to date, I find it unlikely that a PR4 will increase to a 7 or 8 in a short period of time for the next PR googlebar update.

And, there's even a few 0's in the top 100 for search engine marketing. Surely there are more than 100 SEM related sites with a PR of 1 or higher...

Again, consider that Google uses MORE THAN 100 factors and that the SERPS don't show a directly correlation when determining the value of PR.

IMO when considering linking, I'm more concerned with "trust" and "relevancy" than with PR in today's SEO world.