Yellow pages in my opinion are an all or nothing arrangement. Either you go all out with a LARGE ad or you will be looked over. In my experience the Yellow Pages generates a lot of "non-qualified" leads. We just made the decision to go with a simple "courtesy" listing. Decision was made upon analyzing the customer base and finding that only 3 out of all of them were a result of the yellow pages.
You left out referrals...They normally are a SLAM DUNK!