Anecdotal sources suggest that the Pontiac Torrent could go a minimum distance of 10 miles or so (30.73 miles average distance / 62 miles max distance) after the gas light comes on.
Most cars have 1-2 gallons of reserve once the light comes on.
Don't consistently run the tank low. The fuel pump, which on most cars nowadays is mounted inside the tank, cooled an lubricated by the fuel it's immersed in. Running the tank almost empty can starve it of fuel as the fuel sloshes.
Potentially, this can damage the bearings in the pump.
Here are some simple tricks that will definitely help you save fuel--without ripping your car apart from Popularmechanics.com.