On the foredeck is I think the most common since it has the most uncluttered room..It is where I stored mine for almost 15 years of cruising. Some store it under the boom on passages..if they have a skylight it can be cracked open and hopefully no errant water splashes will enter the cabin. Davits have a number of drawbacks for cruising boats since most have vanes and in the med moor stern too. The only problem state side I see is most marinas charge for the overall length of the boat so the dingy on davits would be included. The size and clutter or the deck will determine where you will store yours.
The biggest problem with davits is that they do not suspend the dingy high enough in rough seas and when the boat is heeling. IE: the dingy can fill with water and become a complete nightmare. The foredeck, in my opinion, is also a less than optimal place for a dingy as it may prevent access to the foresail and/or anchor area at a time when access is most needed. Personally, if you have the room and it does not interfere with the boom vang or running rigging, I like the area under the boom on top of the cabin house. Towing it behind is another option if you can 1. get the painter length correct for the seas and 2. don''t mind the drag. Obviously, take the motor off first.