Honey is a natural low-moisture content substance which gives very little for bacteria, yeast, etc. to grow on. So, for the most part, it is pretty safe to add post boil. I would never add honey during the boil, as all the wonderful aromatics quickly boil off.
For convenience, I add honey to my beers during the wort cool-down, usually when below 130-F. I also think adding to the primary is fine too, especially after the yeast have moved past their lag phase and into primary fermentation. Nothing in the honey would be able to compete against a full active fermentation of beer yeast. I prefer unpasteurized honey when I can find it.
Of course, adding after primary works fine too. Just take care not to add any oxygen after primary by excessive stirring or sloshing. Oxidation is not a good flavor for beer, and after the lag phase, the yeast don't need anymore O2 in the beer.