The pilot of a Cessna 177 stated that he planned to fly about 4 hours and 15 minutes without refueling. He estimated the airplane would consume about 8 gallons-per-hour, resulting in a total consumption of 34.4 gallons of fuel, which would leave 13.6 gallons remaining in the 48-gallon fuel system. About 4 hours into the flight, on approach to the destination airport, while flying at 1,300 feet above mean sea level, the engine "sputtered." He turned on the auxiliary fuel pump and subsequently the engine quit. While on the final leg of the approach, the airplane collided with power lines, a tree, and then impacted the ground, damaging the firewall. A Federal Aviation Administration inspector examined the wreckage and stated that the left wing spar was also damaged. The left fuel tank was breeched and the right fuel tank remained intact, but there was no evidence of fuel in the tank or near the accident site. In a written statement by the air traffic controller providing radar service to the accident flight, the pilot stated that he was "out of fuel." Prior to departure, the pilot requested the fuel tanks be "topped off;" however, he did not inspect the fuel tanks during his preflight inspection to verify they were full. The fixed base operator reported that they put 36.4 gallons of fuel into the airplane. About 90 minutes into flight, the pilot increased the mixture to "rich" to alleviate a rough running engine. Prior to the accident flight, the pilot did not report any mechanical malfunctions with the airplane.