Getting your website ranked in a relevant position on the Big Three (Google, Yahoo and Bing) means creating quality content, and lots of it. However, there are other ways to help relevant traffic find its way to your website, and one of those is through the use of online directories. When you list your business on well-qualified directories with good PR scores, it helps to inform the Big Three that your business is alive and thriving. In time, and when used in cooperation with other techniques, you'll become an online authority for your line of business. Search engine prominence won't be far behind. The key is linking to quality content.
So where should you list your business? What directories are reputable? It really depends on your line of business. For example, if you were looking to get your business involved in the lucrative Marcellus Shale development, you might consider listing on The Marcellus Shale Directory. This site has only been around since March of 2012, but it already has a solid PR ranking.
The bottom line: While Google's Panda and Penguin updates have placed a premium on creating quality content, there is still a place in search engine optimization for reputable, niche website directories.