The Messershmitt Me 262 A1a might be the best fighter of WWII, and the antecedent of all modern fighters.
You can argue that the P-51H or P-47N or F6F-3 or F4U-1D were the best piston-engined fighters of the war, and as such did more to win the war.
But in the time of greatest need, the British produced the best fighter plane available in 1940 in just enough numbers for the courageous few to come to the aid of the needful many. That fact alone makes this plane immortal forever.