There are still some good directories that were not hit by Google, but directories work well for local seo. For global rankings they might not be as powerful as they were before but they still have a small effect.
The way Google is fighting back to PBNs is by checking whether the site is active or not, so if you get a link from a static website that has old backlinks and not getting any activity then Google will penalize your site. This is taking effect slowly, so I agree with what Eric said about PBNs being dead by 2016.
So I would advise you to avoid anything that has to do with gaming the system because when it's hit by an algorithm your business is dead and you have to look for the next loophole. So do some real company/business stuff and you'll rank well for a long period of time.
Rely on organic backlinks, don't put backlinks in your internet marketing plan. That's the best advise I can give you.