Ditto, except that it is a bit depressing to watch it dive occassionally into single digits in the truck! Regardless, it has definately focused us on driving habits that are less wasteful.

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you get 40mpg mid + tanks like me in the city. However 55 mpg segments are possible if I timed all the traffic lights on the way to my destination properly.

i got around 20 km a liter when i drove a civic 5 spd using advanced hypermiler techniques
and now I drive a salvage nwh20 prius that gets almost to 25 km/l with 195,000 km to date.

I think it will improve your mileage no matter what. That being said I think that the Civic Hybrid really shines, compared to the regular Civic Auto, when you start getting into stop and go (or slow and go) traffic. The Civic (non-hybrid) Manual appears to allow the driver to get somewhere in between the mileage of the Hybrid and the regular Auto.

I've got a 06 EX Automatic, 90 miles of daily commute and stop and go traffic in amongst that along with some longer shots (5 min between lights) of 50 + mph areas. The trip, particularly in the morning with traffic, is tough on the mileage (35-37mpg is the best I can do). I had one week where I drove that route on Saturday and Sunday (no traffic) as well and the mileage for the tank bumped up above 40 (I've been trying to do that for 6 months).

I think that is an important point about the hybrids, in the real world for most people (living in a urban/suburban landscape) where you run into stop/slow and go traffic (rush hour), they offer tremendous benefits, in mpg terms.

I work at the mileage in the 06 EX auto and its about 10mpg less than a HCH hybrid.