Does the google directory carry much weight?

[Silent_Bob]

I've been browsing my backlinks since the update, and spotted that the google directory backlink to my site is PR7. I was under the impression that if you had one PR7 backlink then your site would automatically become a PR6. Should this google directory backlink carry equal weight to other PR7 backlinks? I have this link, a PR6 odp link, about four more PR6 links, 30-40 PR5 links and a futher 50-60 PR4 links. I'm only a PR5 though. I would have expected to be higher with these backlinks.

Can anyone advise what is necessary to attain a PR6? That is really my target. I've never actively sought links for my site because until the last few months they've never shown up in link:mydomain. Now that they are showing though, I want to get more and reach that PR6. Confusingly, I know one site (run by an seo company I know) that has only 4 backlinks, all PR5, and yet is a PR6. I've noticed that they have high PR outgoing links on their site. Does this play a role in Page Rank too? Its not something I've thought of before.