Okay, I get your point -- so the car just plain gets better gas mileage. My point is, if you drive it like a normal car (some highway, some city), it will get mileage range A, whereas if you push it -- drive lots of long trips, like my housemate's sister does with hers (they 'go somewhere' every weekend) -- it'll get mileage range B, where B > A. It sounds like you were already doing B, if that was a typical profile (I'm not sure how frequently it 'needs' to be driven lengthily, I doubt it's once a week -- but I am by no means an expert). I'm just saying if you drive it like a normal car, you won't get as good gas mileage as you would if you drive it lengthily, although that still may be better than a regular gas car. My housemate gets 50 when she goes to Pennsylvania or whatnot, and usually gets 40-45 (we live close enough to DC that everything counts as city driving, even halfway around the beltway). I think.
I guess my point is, 43 is yes, still better than 27 (what I get), but not as much better as 48 would be, and certainly not better than 70 (what that theoretical diesel electric hybrid would get).
I'll have to ask what my cousin gets -- he has a hybrid. I'm pretty sure it's better than 43. He drives from Sterling to downtown DC 5 days a week, and allots $20 in his budget for gas every week. And it's emitting very little in the way of emissions when the engine is off.
Oh, and here...I'm sure it's biased...