I like the big 5 of US Air Force WWII planes, P-38, P-51, P-47, P-40 and P-39. Yes, even the little P-39.
Aside from that I like the Corsair, the Spitfire, Bf 109, Yak-7, and the Hawker Typhoon. My hats off to the British for making some of the most agile, and to the Germans for beating us in aircraft technology, like the Me 262 and Jet bombers.