Per fueleconomy.gov's numbers, you're going to save something like $800/year in fuel.
Personally I can say it was a lot nicer filling up with my previous car getting ~20mpg compared to my current car getting 14. You can drive to the next town without seeing your gas gas swing 1/4 tank.
Interestingly, the premium is $3-4k for vehicles with comparable mileage. $33k for a hybrid with 40,000 miles vs $30k for the non-hybrid. I would really consider it if I was to purchase one, it's about a 43% bump in your city fuel mileage.