It’s nice that the price of gasoline is relatively low again. At $1.73 a gallon, the current average price here in Massachusetts according to AAA, I feel much better taking our other car, a gas-guzzlin’, low-production, high-speed ’89 BMW, out to exercise my lead foot. But when thinking ahead for the best car we’ll want to buy in the future, I’m not planning for the most power money can buy. It’s hardly a bet that gasoline will once again be pushing $4 a gallon. Will it be next week or even a year from now? Maybe not. The U.S....