Hans-Joachim Marseille might have been the top scorer if he'd lived long enough. He racked up a high score in North Africa, but was killed with a tally of 158 in September '42. His Bf109 suffered a fault and the cockpit filled with smoke; he bailed out, struck the tailplane and was either killed instantly or knocked unconscious and thus couldn't deploy his parachute.
His score is open to question, though - I forget the precise details, but there is a debate over whether he falsified victories (claim made by a distinguished RAF veteran, I forget which); whether he had victories falsified for him by Goebbels for propaganda purposes (forget the source for that one) or whether some claims stemmed from the usual cause of confusion (aircraft dives away apparently out of control and streaming smoke but actually got home safely, etc, etc).