Well, gas is not yet $4 a gallon but to contemplate what a $4/gallon society in today's standards would not be a good thing. I thought Letters at 3AM was an interesting article.
Here's a snippet:
......"Gas prices can only go up. Oil production is at or near peak capacity. The U.S. must compete for oil with China, the fastest-growing colossus in history. But the U.S. also must borrow $2 billion a day to remain solvent, nearly half of that from China and her neighbors, while they supply most of our manufacturing ("Benson's Economic and Market Trends," quoted in Asia Times Online) – so we have no cards to play with China, even militarily. (You can't war with the bankers who finance your army and the factories that supply your stores.) China now determines oil demand, and the U.S. has no long-term way to influence prices. That means $4 a gallon by next spring, and rising – $5, then $6, probably $10 by 2010 or thereabouts. Their economy can afford it; ours can't. We may hobble along with more or less the same way of life for the next dollar or so of hikes, but at around $4 America changes. Drastically.".......
Let's hope it doesn't get that badly.