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Turning the AC off before turning off your car shouldn't help the battery charge any more than if you left it on. The AC is through a mechanical linkage via a belt and thus puts a mechanical strain on the engine and should have no bearing on the electrical system. The alternator runs off the same mechanical linkage, but the engine doesn't run slower with the AC on. In fact often times in my car the engine idles faster with the AC on rather than off, so the alternator would charge the battery more at idle than with the AC off. Unless the AC has some kind of extra electrical system that I'm not aware of then turning the AC off a few minutes before shutting off the car won't help your battery.
Running the AC while recycling is definitely a more efficient way to go. Running the heater with recycle on is also a more efficient way to go if you want to heat your car faster or run the heater less, but since running the heater also assists the engine cooling system then it's probably more efficient for the engine to leave the outside air coming in.
Having the AC off before turning on your car is definitely helpful for the battery, however it's also helpful for your compressor.
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