I usually see "emotion" as being the biggest factor in making decisions. Logic doesn't seem to be the major factor. A great example was that of my cousin buying a car just recently. He commutes about 45miles one way each day. Because he doesn't make a lot of money, it logically makes more sense to buy a car that's economical on gas like a hybrid. So what does he buy? A V-8 hemi SUV.
He bought it because it looked cooler and because he could "fix" it up.
If you're talking about the Durango, then the models after 2006 or so have an MDS system that shuts down half the cylinders when it's cruising.
These sorts of systems can give surprising reductions to fuel consumption. For instance, with the V6 engine, the new Camaro gets better highway fuel economy than a non-hybrid Camry.
Personally, I think that worrying about vehicle choice is pretty far down the list in terms of reducing commuting cost and environmental impact. Think of it this way:
Annual commuting cost = [fixed costs] + ([# of commuting days] x [commuting distance] x [cost per mile] / [# of people in vehicle])
Changing your vehicle only affects one variable: cost per mile. And you usually have to spend a fair bit to make a small impact. You get much more bang for the buck if you switch travel modes (i.e. car to transit), carpool, or reduce your live-work distance either by moving closer to your office or getting a new job.
Or take telecommuting: if you can work from home 1 day a week, then you reduce your fuel consumption by 20% with virtually no cost. That's comparable to the reduction in fuel consumption you'd get from switching from conventional gas to hybrid.
Speaking for myself, I drive a 20-year-old SUV. However, I also recently reduced my daily commuting distance by 90% (yes, 90 percent) and now
walk home from work when I can. If I did switch to a hybrid, it wouldn't reduce my fuel consumption that much.
Personally, I think that if you're driving 45 miles to work every day, then you're not really trying to reduce your fuel consumption anyhow.