If you are going for your PADI AOW cert Deep, and Nav are required. Most places have you do night as well. As was stated before, PPB is a good class to take it will help you with your diving no matter where you dive. It will mainly help with your air consumption, and over all comfort in the water. I would suggest taking a good look at what kind of diving you plan on doing, and where you would like to go with your diving (ie. do you eventually plan on going pro). If you don`t plan on going for your DM, then take some fun classes UW Photography, Search and Recovery. Or go easy and do your Boat, Computer/Multi level. When you do decide to get your AOW like I said take a good long look at what you want to do down the road and pick your specialties accordingly. Just remember the PADI motto "If you`re not learning we`re not earning" :) Good luck to you Scott J