My immediate reaction is the P-47-D30. Stang's are not tough enough to do attack IMHO.
But with a bit of though... I have to say the F4U-1C. It's guns are better on armour and to top it off you can fly it from a carrier. Carrier ops make it more flexible than most of it's competitors, so it wins the best all-around IMHO.
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Lephturn - Chief Trainer
A member of The Flying Pigs
http://www.flyingpigs.com "A pig is a jolly companion, Boar, sow, barrow, or gilt --
A pig is a pal, who'll boost your morale, Though mountains may topple and tilt.
When they've blackballed, bamboozled, and burned you, When they've turned on you, Tory and Whig,
Though you may be thrown over by Tabby and Rover, You'll never go wrong with a pig, a pig,
You'll never go wrong with a pig!" -- Thomas Pynchon, "Gravity's Rainbow"