Networking with follow-up is the most effective. The key to a successful job search is contacts. Most people can sell themselves better in person than on paper. While the tailored resumes you send to search firms, ads and direct mail targets are important and deserve your attention, they will never possess the power of a good relationship.

No one can help you in holding a good job except Old Man You.
Edgar Watson Howe

Executive search firms need a good resume from you, but they also must have a search assignment that matches your background before they can be of service. Headhunters do not market you. They find the best candidates for client job openings. Their clients are companies that pay their fee or retainer. Don't expect a headhunter to make you her number one marketing project. Conducting your search campaign isn't her job, it's yours.