First, the price of a barrel of crude oil, in 1999 dollars:
(Courtesy of Wikipedia)
As you can see, our current prices of $60/barrel are high, but the 1981 peak price is about $70/barrel when adjusted for inflation.
I've expected for a while that our current steady climb in prices will not stop until we have reached at least $2.50 for a gallon of gas. (My corner station is currently selling the lowest-grade gas for $2.39.) Looking at this graph, I would guess that most of the population will start doing something to curb their gasoline use when the price rises to $2.75 or more, since the record high is just over $3 in today's dollars.
One side benefit to being a one-job family: we're using less than half the gasoline we did before. :)