The only real weight I give to
PR when evaluating whether or not I want to link to/with a site is if the site has been online for more than a year, I want them to have at least a PR1, indicating they're not being banned by Google. Beyond that, I could less honestly. I'm more concerned with the site's content and relevancy to my site. I also check to see who else is linking to them, who they are linking to and finally, I check whois to ensure they're not on a blacklisted host.