Test drive a hybrid via NY Times
All three Civic sedans have their merits and each appeals to particular sensibilities. For the best driving experience, the conventional EX is the hands-down winner. Save-the-planet types can take heart in either the Civic Hybrid or GX, since both have emissions as low as anything but an all-electric vehicle. The Hybrid uses the least fossil fuel, but it still adds to the coffers of OPEC. The natural gas GX is not only the cleanest car sold in America, it contributes to the nation’s energy independence by using a domestic fuel in plentiful supply. But the GX is simply not available — yet — in most of the United States, so the Hybrid may be the best compromise.
While I wouldn't think about driving a natural gas car, I might consider a hybrid or a diesel if I were on the market for a car. But I definitley wouldn't check out anything before reading up on the Consumer Report's guide to fuel efficient vehicles which compares EVERYTHING on the road (and you'd be surprised, it's not just the SUV's that are gas guzzlers...)