I don't think you'd ever answer with a dollar figure. You say you expect to earn a competitive salary for whatever specialty you go into, but that the money is secondary to being able to do X, Y and Z. It's really just an opening for you to talk about your goals a how you define career satisfaction. Giving a Dollar figure or refusing to answer are both the wrong approach.
Sounds like a terribly phrased question, but I probably would have said it doesn't matter as long as I get to live comfortably with my family and get to do x,y,z, as above poster said.