Some head hunters (at least in the past) only collect money if you stay with the agency for X amount of days (90?). Anyway, the company I just left "only" uses temp agencies to find their employees. A lot of them do that now. They hire from the temp for 60-90 days to make sure they'll work out and then hire them. It's cheaper for the company this way because they don't want to invest in insurance, etc., for someone that may not work out.
I had a 3 yr break in my govt job and I went to temp agencies for work during that time. I got asked to stay by every company I temped for and was able to pick & choose where I wanted to be. Also, sign up at several agencies.