A lot of issues here!
Firstly, why are you worried about
PR! Surely the most important thing is you position in the SERPS.
100 directories? Take care that you are not on black hat ones. It is believed that Google is currently not looking favourably on sites that exist simply to provide links.
Better just a few good-quality links and this really is hard work. Best to examine to page you link to/links to you to be sure that it has revelent content.
I don't even bother too much about the
PR of the page. I feel that if they have the right content and attitude towards linking it will be good for both of us.
Even if the
SEO does not need tweaking, I think that it is a good idea to make regualr changes, say every couple of weeks.
The thinking is that if googlebot seems the same stuff on every visit she won't revisit so regularly.
Finally you should optimise your signature, like mine. SREF is very good at getting posts optimised. If you have links and optimised anchor text in your signature you could get a link every time you post.
Researching a good topic, writing articles and posting to forums (especially SREF) is probably far more effective than linking to 100's of directories.
Howver, take care because Richie does not like blatant self-promotion.
Homefinder
Is there a PR update again? 
Linear Mode
