The pilot was flying his airplane to his home airport following an annual inspection. Ground operations and the preflight inspection were routine, and the weather was “clear and calm.” During the takeoff roll and shortly after takeoff, he noticed that the engines were not running smoothly. Rather than continue over the mountains to his destination, he elected to return to the departure airport. As he set up for landing, he was anxious and “high and a little fast” on the approach. After touchdown, the airplane bounced and veered slightly left as he applied the brakes and retarded the throttles. The airplane departed the end of the runway, the nose landing gear collapsed, and the airplane nosed down in the grass. A Federal Aviation Administration inspector reported that the propellers contacted the ground and the lower fuselage and right wing root were substantially damaged. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot further stated that he did not fly a stabilized final approach.