On Saturday driving my 2004 Toyota Solara back from Denver I drove all day on one tank of gas. I covered 520.4 miles. I thought at the time that this was a personal record for distance driven on one tank but was surprised to find upon checking that in the first couple of years after buying my previous car (a 1986 Toyota Celica) in 1994 I had exceeded 500 miles on a tank on several occasions and in August 1995 had gone 523.4 miles.
The Celica got better mileage but had a smaller gas tank than the Solara so its range was similar. The Solara has an average mpg calculator which I reset each time I buy gas. It generally overestimates mpg by .5 or so (compared to dividing mileage by amount of gas required at the next fill up) but on Saturday was dead on estimating 34.0 mpg (as compared to 34.01 computed from the 15.300 gallons to fill up). The Celica required 13.472 gallons to fill (after the 523.4 mile run) for an estimated mpg of 38.86. Both cars have a reserve (if the specs in the owners manual for fuel tank capacity are to be believed) past the point where the gauge reads empty so the true maximum range is a bit higher.
Of course to be really precise you need to account for the fact that the Celica's odometer read about 2.4% high while the Solara's reads about 2.4% low which would mean the Solara holds the true miles record.
One problem for electric cars is that there is no prospect of their achieving a range of anywhere close to 500 miles anytime soon. And they take hours to recharge as opposed to a few minutes to refill a gas tank.