With the ENY I think the P47D-11, F4U-1, 109F-4/G-2 and 190A-5 are the best. All of them have advantages and weakensses (none have a good bomb load), but on balance they can all be very lethal to any plane in the game and it would be hard to imagine a situation where any would be locked out from the ENY system. The F4F is one of the best base defence perk harvester's too.
Without ENY, the usual suspects, La7, 51-D, 190D-9, Spit 9.