Folks, I got some excellent advice from reading an Israeli security consultant named Juval Aviv: He always recommends keeping at least a half of a tank in your vehicle at all times, since, in a SHTF situation, the power may be knocked out, gas stations may not be able to pump any gas that they have, and ATM machines may be knocked out as well.
I have followed this strategy since last year when I first read that advice and it has served me well throughout the present gas panic in the Piedmont area of NC.
I avoided the worst of the panic immediately before and after Hurricane Ike and in weeks to follow. I am able to go about a week between half-tank fillings, then, when I had to re-fuel, I pumped during evening hours when there were fewer people lined up at the pumps and when gas was cooler. If you pump at night when the gas is cooler and less vaporous, you can get up to 10 percent more gasoline in your vehicle that way.
Oh, and as long as your owner's manual doesn't specify that you must use high octane fuel, the regular octane is just fine. I have no complaints about using regular octane.
It is so much fun being prepared and far from the maddening crowd of sheeple! Now, when I go on my lunch break, I watch the nearby gas pumps just for sport!