Don't deliberately screw yourself over. Don't accept less than the average for your position and either point blank refuse to give them negotiating leverage by telling them your current salary or lie.
For better, longer advice see ［Salary Negotiation for Software Engineers］(http://www.kalzumeus.com/2012/01/23/salary-negotiation)
I'm afraid I couldn't quite bring myself to follow all the advice in your link, but at any rate I increased my number to 125k. So, it helped a bit. :)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.