This USA Today article on hypermiling – there are a lot of articles on hypermiling these days! – says that 100 mpg is not at all uncommon.
So if you picked up hypermiling techniques and doubled your gas mileage, you would be paying an effective $2 per gallon. Tripling your gas mileage would push it down to $1.6 – a range we haven’t seen in quite some time.
Maybe a better way to figuring out how far away a place is is the cost to get there. “I live $4 from the nearest mall.” Which would be $8 round trip. That certainly puts things in a different perspective!