P-47N.
Of course, it is far from the best in typical low altitude MA furballs. But it absolutely rules the thin air and thus can always hold the high ground and attack from advantage. It can range with anything. It is reliable, was relatively easy to fly, has good visibility, is armed to a fare-thee-well, and so rugged that it was difficult to shoot down even if you managed to get an even break with one. Thus, under actual "war" conditions, faced with level bombers escorted by P-47Ns at 30K+, a belligerent nation could choose between attempting interception and fighting the Jugs in their playground, or simply allowing their infrastructure to be reduced to rubble.
