At the last job interview I went to the question of my required salary came up towards the end. I had specifically said on the application form that it was the minimum I would consider. The principle interviewer said that my required was a bit high and that he would struggle to get it approved by the powers that be. So he proposed I go in at a lower salary and we would review it after 6 months. 'would I be happy with that?'.
Now, I was not all that impressed to tell the truth because I had specifically said that it was a minimum. So I said no, I'm sorry but I wouldn't be happy with that. Well, the look on his face was worth travelling half way across the country for and the guy sat next to him laughed out loud. He gave me a very hard look and leaned over the table and said, 'so, you are saying, if we offered you a job at x salary you would turn us down'. Yes I said. I'm a professional, I do a top class professional job and I don't want to put myself in a position where I am distracted by being dissatisfied with salary.
Long story short, they offered me the job at my required salary but I turned them down anyway. They did contact me and offer to negotiate (presumably upwards) but I had allready mentally moved on by then so I still turned them down.
So, my advice, don't sell yourself short. Tell them what you want but have a reason to justify it. If they try to beat you down and you really want the job try to get a 6 month review included instead.