P-51
F4U
Spitfire
FW-190
Bf-109
Lancaster
B-29
B-17
Ju-88/B-25 (They make my list because of their versatility and I consider them tied)
Me-262 (in 1-on-1 combat, you couldn't touch it)
That really only scratches the surface though, there were so many planes that come within an ace of each other in therms of quality. I have really gone for planes that were produced in significant numbers as well as had excellent performance.