An alternate point of view.
MPG Illusion, gallons per mile, GPM, GPKM
Plug in the numbers and you will see not to sweat the small stuff. According to Fuelly, there is only a 3 MPG real world difference between the Prius and the Insight. Even at 4 or more bucks a gallon, the annual fuel cost and over many years is negligible. As long as you're getting at least 40 MPG per tank, you're doing great.
Our Insights are a very good bang for our buck. Feel great about your Insight Purchase. The premium people pay for a Prius will never even come close to being recouped. Even the Civic Hybrid isn't looking so hot when you consider the extra cost. Actually the regular Civic or Fit is a better bang for your buck.
BTW, I'm not advocating not trying to get the best fuel economy you can. There are environmental considerations as well. Besides, trying to get high MPG is fun.