According to the pilot, prior to departure he calculated that he had 3.5 hours of usable fuel for the two hour and 15 minute flight. In addition, he indicated that the average fuel consumption was eight gallons per hour. He performed a preflight inspection, and noted that the fuel gauges indicated about three-quarters full, which he believed to be about 20 to 30 gallons of fuel. On climb out, the oil door on the engine cowling opened and the pilot returned to the departure airport to close it. After landing the pilot taxied to the ramp, to secure the door and then departed again. The cross country flight was uneventful and the pilot requested a straight in approach to the destination airport. He was performing a gradual descent about six miles from the airport when the engine lost total power. The pilot attempted to land at the destination airport, but the airplane descended into trees and impacted the ground in a residential area resulting in substantial damage to the fuselage, wings, and empennage. A post accident examination of the airplane revealed that the fuel tanks were not breached and recovery personnel removed 1.5 gallons of fuel total from the airplane. An examination of the engine revealed no anomalies that would have precluded normal operation. The pilot believed that the airplane had a fuel capacity of 42 gallons and according to the owner's manual; the airplane had a fuel capacity of 39 gallons, of which 36 gallons were usable.