We find that it's hard to make the math work on hybrids vs gas models of the same vehicle, the payback is very long term. For long highway commutes there are several vehicles that will get around 40 MPG. We always tell pilots that a few knots won't make much difference on their trips, same thing with cars a couple MPG is pretty insignificant over the course of a year. Buy what's comfortable that gets 35+ and you'll be happy.
20K @ 40 MPG is 500 gallons per year, 20K @ 35 MPG is 571 gallons, 71 gallons @ $2.30 is $163.00 per year.
not a lot of difference if it's a more comfortable ride!