I just got my 2006 HCH about a week ago, and have driven a little over 200 miles. The average MPG is about 37. This is with me driving very conservatively (but nowhere near hypermiler standards I'm sure).

My carpool mate purchased a Toyota Camry Hybrid about a month ago. He's getting only a mile or two less than my Civic, and I would say is driving less conservatively than I am. The Camry by the way is very impressive - lots of room, great ride, more power, more features, and not much more money (he paid MSRP, I paid $1500 over). I bought the Civic because the Camry did not qualify for the carpool lane sticker in California.

So, I've got my tires at 35 psi (tried 38 and hated it), am using the A/C way less than I'd like to, and driving like my grandmother and getting 37 mpg.

I figured I'd at least be able to get over 40 and drive the car "like a regular car" and drive the speed limit on the freeway etc.

I've heard about an MPG increase after 3500 miles but am not sure what to expect in terms of the number.

I'm in serious buyer's remorse mode at the moment (just in case you couldn't tell...)