Fuel, cars and where is my money sitting?

In my garage sits a very comfortable eight-year old German Sedan. The other vehicle, an American made SUV also spends less time on the road. As gas prices continue to rise, and I spend more of my working time in my home office I am guessing this trend will continue. My car is worth about 10% of the replacement purchase price. That amounts to several thousand dollars just sitting there and arguably not increasing my net worth. But if it were a newer car, I would have even more concern owning such an expensive dwindling asset given its limited use. It occurs to me that the rising gas prices will not only impact the type of car we buy, but how much we are willing to spend. Additionally, maybe I should think of it more in terms of an expense... and seek to have $0 in equity. Will I ever again want to fully payoff a car loan?