Are you talking about just pure A2A attack? Or a mix of ground attack as well?
I'll assume the question asks "pure loadout, overall."
In this case, the answer is the P-47D series. (I prefer the P-47D-25 myself.)
Eight .50 calibur MGs with 3400 rounds, plus you can slap on two 1,000 lb bombs, a 500 lb bomb on the center pylon, and (someone correct me if I'm wrong here) 10 HVAR rockets on the wing pylons. (this would be the loadout for the P-47D-40. The D-25 cannot load HVARs but the smaller yielding versions)
Each HVAR class rocket yields ABOUT 230 lbs of ordinance, which if you total it all up, the P-47D can carry a maximum of roughly 4,800 lbs.
This is more then enough to destroy any GV on the ground, or any hanger that stands on the field.
It's a little more than half what is needed to sink a CV, which means potentially two fully loaded P-47D's could drop a CV battle group (assuming it takes 8,000 lbs to sink a CV).
Dunno 'bout you fellas but this plane says "pure pwnage" to me.

P.S.
Btw, I'd rather fly a P-47D-25 light into A2A combat then any of the Fockewulf series.