I'd go with dry sand. I'm skeptical of what is still alive in a bag of sand that has been sitting on a shelf.
Regardless of what kind of sand you get. You should add it slowly. Over the course of a few days. Longer if your situation permits. Do not add all the sand at once. it will start a cycle and your tank can crash. I do suggest going with dry if your tank has already cycled and is established. THat way you dont have to worry about the die off on the wet sand. Also make sure you rinse it with RO water so it does not cloud up you tank with the fine dust. This is what i have done everytime i have added new sand to my system and had no problems.