Links from article directories no longer carry significant weight since the Penguin update introduced by Google a couple of months ago. And popular article directories used to be capable of bringing in traffic to your website indirectly as they tend to rank high in the search results. However, things changed when Panda was introduced.
Because of the reasons above, I would rather stay away from article directories, at least for now, and opt to pitch for guest blogging opportunities on "picky blogs".
Here's a video on link building methods that you should adopt post-Panda and Penguin: http://www.seomoz.org/blog/the-death-of-link-building-and-the-rebirth-of-link-earning-whiteboard-friday