| What the HR people are often looking for are two things: what you think you're worth and what you've grown accustomed to. Many things can be derived from those two points, even if most of these "things" are pure BS.
What I would do is find out what the market average is for the job being offered, taking into account the entire compensation package they might be offering if you know it. My wife has a superb benefits package from the university which employs her, so making a little less than top-rate dollars is okay by her.
Once you find the average, determine for yourself if you're better or worse than the average worker in that position. Do a wild-arse guess as to how much better or worse and the rest is arithmetic. Don't sell yourself short!
One of many resources for finding salaries: [$alary.com] | 
