My next car (I drive a 1999 Honda Civic) will almost certainly be a hybrid of some sort. But what I have now gets about 24 mpg in the city and over 30 on the highway and has only about 104,000 miles on it so I plan to keep it a while longer. Probably at least until my wife's Element (18 city, 25 highway) is paid off.

Perhaps by then Honda will have a hybrid Element.... (Yes, I am aware of the trade-offs with the hybrids. I make enough money to cover the bills, but I fail to see why I should pay those of the oil companies as well.)