My personal best was 409.9 miles on a tank. I coasted into a station and refilled it with 15.117 gallons (27.12 mpg). I did that once just to see how far down the gauge goes.
My commute is mostly hiway. I keep it around 80 mph when traffic permits, but there's always some slow-n-go or stop-n-go. I routinely get 350 miles (+/-) on a tank.