The following chart is from inflationdata.com and it shows average gas prices from 1918 to the present day. The red line shows inflation adjusted gas prices. In other words, how much gas cost in past years, translated into todays rates.
It's interesting to see how gas prices have been either holding steady or trending downwards right up to the crisis in the 70's and into the early 80's. After that, the prices shot back down until Katrina hit.
It gives me hope to think the red line could come back 'down' in the next few years. Unfortunately, if you look carefully at the black line, you'll see that the actual price of gas probably won't go back down.
Found via: autoblog, auto prophet