I just started a new job about 5 months ago. I started as a contractor for the first 6 weeks, then converted. This initial contracting period allowed me to demonstrate that they needed me. I impressed my team lead and he went to the director and fought for me. The director decided to bring me in at a lower paygrade, but that allowed me to demand both a small signing bonus and an accelerated review schedule. (I'm actually in the process of my three month review and I have a 6-month and one at a year.)

Although this wasn't in the initial agreement, my team lead has been very flexible when it comes to telecommute time and flextime. He knows I work some nights and, more importantly, he knows I produce. Given that, he shows me a little love.

Another thing to look at is what you'll be working on and what you can receive training for. Maybe they'll only pay you 80% of what you want, but they'll spend 40% of that on training you. You can take that training and use it as leverage a year down the line. "Give me more money or I walk." If you're a known producer, that's very potent stuff.