[jonathan180iq]

Just as little mathematical comparison:

At 67 miles per gallon @ $3.50 per gallon, I got .1914 miles per penny worth of gas.
At 74 miles per gallon @ $3.60 per gallon, I got .2055 miles per penny worth of gas.

In order to be worth the extra cost, I would need to travel at least 2.055 miles further per gallon of fuel in the fuel tank.
Assuming a 4 gallon tank, that would mean I would need to travel an additional 8.22 miles.

Well, in real world driving, I have achieved up to an additional 28 miles per tank by using non-ethanol gas. A total savings of 136 cents ($1.36) over regular fuel.

-The math will be different for every vehicle. But it is worth the extra cost, at least in the GZ. However, if you have to drive 30 miles to find a gas station that doesn't sell ethanol, then you have wasted any potential savings during the trip. I was lucky enough to have an ethanol free station located on the main drag just before the interstate.
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EDIT:Using the same math, it should become easy to see why using premium fuel is a waste of money. Even assuming a best-case scenario in which your fuel economy does not decrease with the use of premium fuel, you are instantly wasting money.