The links are not what makes directory submission worth doing. You will only see benefits from submitting to high profile directories that will actually stand a chance to send real traffic. Google does not care about directories that noone uses.
You are best off submitting your website to content distribution networks that provide your company's information to sites like Manta and Yelp. This is the most effective, Google-kosher way to submit to a large amount of directories and be rewarded for it.