Just wondering if there is a chart/table or general rule as to what a listing in a high PR directory would do for your websites traffic? Eg. 1 listing in a PR6 directory would mean an X% increase in traffic to your site? Are there general guidelines for this sort of thing? Anything that helps put together a benefit/cost ratio?
it depends on the status of your site. if you have 0 incoming links and your site isn't indexed, getting a link from a PR6 directory would increase your traffic by an infinite percentage for any established site I wouldn't bother paying for directory inclusion in most cases. it likely won't make any noticable difference at all.