Directories are not as powerful as they used to be but they are a part of my seo efforts and I believe they work well. Stick with directories that target your niche or at least have your niche category. I have very competitive keywords that I build for and many of the top guys (top 5 1st page Google) are using directories. You need to build on many different platforms to put a site at the top and stay there, keyword "stay there". Anyone can link blast a site and get to the first page, Google gets tricked into thinking the site is popular, problem is it only last for a week or 2....if that long. How do think all these guys make money that are claiming they can get you to the first page for x amount of dollars.....they can, the problem is they don't tell you that it will gone in a week and probably penalized....