Personally, I prefer the pompoms on my battleships. They're light, fast firing and have a rather fast reload time.
On the carrier (Malta), I prefer the D version of the 5.25" RP12 guns. I load enough AA to kill incoming aircraft that get left at default height.
And some of the LHE ammo for those games where I find myself having crappy teammates. I just shoot charging ships that are focused on something else. *cough* DDs *cough*