I worked for a company on Memorial Drive in Cambridge MA. When I was getting restless we had the 'what will it take to get you to stay?' talk. My answer was a keycard for the underground parking lot. The company had an outside parking area down the street where I'd leave the car during the week but when you drive a Firebird in Boston it's always a pleasant surprise when you go back and the car is still there.
I stayed for another project before leaving. Between the parking space and a new project I was content for another year.
That also illustrates the disconnect between HR and technical people. HR thinks in terms of raises, nerds think in terms of challenges.