insightcentral.net Citrus Smoothie has posted there info on the new Honda Civic Hybrid, including its mpg:

56 mpg city; 54 mpg highway; 55 mpg combined
( Prius II is 60 city 51 highway 55 combined ).

This info is from "recent Insight Owners Day at Honda UK" ; apparently Honda had an IMA expert there.

The new Honda Civic Hybrid should have a $2350 tax credit.

It would have to be improved to almost 60 mpg city to get the same tax credit as the Prius II.
Assumptions: The mpg is US gallons, but it is not certain that the fuel efficiency quoted is based on the EPA tests or on European tests. I assume it is US EPA.
--Walter