Depends on your skill sets and years of experience.
I am currently in a full time position now, but have spent a significant amount of time lately interviewing contract-to-perm applicants for a backfill.
We've been going through recruiters for the resumes, so they obviously tack on their 10%-15%, but the numbers ranged from $55/hr on up to $120/hr
I was really surprised that many of the applicants I would qualify as a JR Admin at best were asking around $60-$75.
Someone correct me if I'm wrong, but I'd say, start with $45-$50/hr and tack on $3/hr per year of experience you have. If you think you are really good, maybe $5/hr per year of exp.
Remember don't price yourself out of the market.