It would almost certainly be true that you get more bang for the buck by targetting transportation.  I guess I am thinking that you might have elderly folks out there who don't drive much and still have oil heat, and these people are going to be in a real fix if heating oil prices go up.

For the rest of us though, vehicles are probably where we need to focus our attention.

Why worry, Eric?  Won't the market take care of these "elderly folks"? ;)

Seriously though, there's a lot of low hanging fruit in increasing a home's thermal efficiency.  Checking weather stripping on doors and replacing it where necessary is a good place to start.  Making a cheap frame out of 3/4"x3/4" wood to fit in the inside and/or outside window well, stretching and stapling clear plastic across the frame, and tacking the whole structure in place with finishing nails (so you can remove it come spring) gets you a fair buck for the bang too.  This worked surprisingly well on my basement windows.  A day later the basement was comfortable rather than chilly.  But natural gas would have to get pretty darned expensive before my wife would accept such "window treatments" on our more visible windows.

It won't change the big picture like focusing on transportation, but it's still worth doing.  I don't think a retired couple that turns off the heat in February so that they can afford March's medication is thinking much about that big picture.  (And I've consoled several members of such couples at the bus stop the last two winters.)