Directories can still provide useful backlinks, unlike what many self-proclaimed experts have you thinking. However, you should never pay for links from directories, unless you are sure that they will throw some traffic your way.
Many directories are made with the sole purpose of making money from unsuspecting website owners, these directories often brag about the pagerank of their front page, in an attempt to make website owners think that links from their directory is more valuable. The front page pagerank has no effect on the link-juice passed on by a sites sub-pages.
Things to include in your considerations when looking for good directories, would be their current traffic state. I.e. Is the directory actually used by users? If it isn't used by users, what other benefits are there to having your site listed?
The state of Directories
Most directories are useless for users, and doesn't have any other purpose than to provide backlinks. In other words, to function as a link-farm for SEO purposes.
Some directories however, may still have some degree of usefulness. But these are usually on-topic ones, that are hard to get listed in. It should also be mentioned, that data from directories sometimes gets used by other websites.