You need to look at it this way:
Popularity
vs.
Effectiveness
In a
popularity contest, you'll see the Spit 16, P-51D, NIK-2J, and La-7 as the top fighters. In
reality (in a virtual game, scary

), that will go to F4U-4 hands down.
Best attacker? Well for most popular you'd see a mixed response, but top three would be a P-38L, P-51D, and P-47N/D-40, and this is true, with the addition of the A-20 and other variants of the Mustang, Lightning and Thunderbolt.
Now, the best bomber? There is a few ways to look at this question. Ord, Speed, Defensive firepower, and looks. The B-17G probably takes the cake here as best overall bomber and most popular (closely followed by the B-24J).
Gv? simple. Tiger, in both practicality and popularity. Even through all the whines tankers have put up regarding the Firefly, its still the king.