I've always used mines for naval if the aircraft had them for the load out. Mines are set and left, and can deny the enemy a large area, where as fired ordnance you have to see your target. Since you can spread mines in a greater area, your chances of actually interdicting something is greater. If an aircraft doesn't carry mines, I'll put rockets on them, and if they don't have that, I put bombs/torpedos. In all the games I've played, mines are by far the best loadout for naval interdiction.
For tactical air, if I'm going after tank formations or rail way interdiction, I use rockets, and for bombing infantry units I'll use small bombs. Normally I won't bomb just units, unless there's a juicy stack of armor sitting around. Ground interdiction and rail way are probably the two most important tactical air aspects, and FB works best at railway, and heavies are best at ground.
For heavy bombers, I use large bombs to take out the subs. As for other load outs, it's also dependent on how far the target is. If in doubt with bomber command, load incendiaries. Incendiaries dropped in a hex have a chance to damage other industry in the hex. Normally, I have bomber command using incendiaries to take out manpower and some heavy industry, and the 8th will be hitting heavy industry and other factories. Since the 8th doesn't carry an incendiary load, it's not that great at taking out manpower. When your not flying as far, increase your bomb loads, and vice versa. Sometimes you have to take a smaller load to reach the target.