Interview with the Headhunter
Scott Reeves has an article on how to work with recruiters: Acing the headhunter. Anthony adds some recruiter perspective and additional tips: How to interview with a headhunter:
By treating the headhunter as your partner—not your obstacle. By being totally honest and upfront with him/her. By showing him/her that you have reasonable expectations and are willing to listen to their advice.
Don't come off as a prima donna. Don't be rude to the staff. Don't show up in casual clothes. In short don't treat the headhunter as a useless middleman.
And above all don't get hostile or refuse to answer certain questions (unless they are obviously illegal). That is a major red flag.
Whether you like the term headhunter or not, a good recruiter is good to know.