$10/gallon gasoline in the US will prompt a war with someone. the oil embargo of the 70's and 80's almost did that (and actually touched off smaller skirmishes).

$6/gallon gas will cripple the US and flood our illustrious neighbors like Venezuela, Iran, and other nations with lots of dough, because developing nations will have no choice but to buy it (allbeit less, but still).

We have no other sources of energy available (at any cost) right now to handle the huge appetite for energy here in US, even if we combine all current technologies. We might be able to "ramp up" production of alternative energy (if we ignored permitting) to meet our CURRENT consumption in a decade or so...

If we were cut off of oil today, I'd buy a steam powered car. Technology already exists, fuel is readily sourced, and range is unlimited as long as water and combustibles are around. Sure, my carbon footprint won't go away, but I'd probably not lose much sleep over my "footprint" vs. my ability to feed myself.

Probably wouldn't be working in a nice little office, either. Will need to brush up on my farming/hunting skills (gator tastes pretty good when sauteed properly), and possibly loot a local tractor supply store and/or farm equipment dealer.