The "Pre-Reqs" piece is not right. You really don't need to have another job offer or a current job to negotiate. A while ago I wrote up this script for how to negotiate a job offer with no leverage at all when you intend to accept it no matter what: http://bit.ly/1185CGm Most job offers come with leeway for negotiation, regardless of your situation. All you really have to do is ask.
>You really don't need to have another job offer or a current job to negotiate. No, but if I know that you don't have another option, I'm not going to be as willing to give up more. A known secondary option puts pressure (sometimes, tremendous) on your negotiating partner. The absence of such an option does not. That's what the article is saying.
When you get the chance to say "I do have one other offer that is expecting a response by $date, but I am really interested in this position, so I wanted to see if it was a good fit before committing to the other. Do you think that is enough time for us to meet?"
Suddenly, mountains start moving.