This depends on how often you go diving and what your goals are and how much money you want to spend. Do you just want a few shots to remember the dive or are you looking for shots to frame? Do you want video, still shots or both? GoPro is of course one of the first to come to mind, and easily accessible. Olympus has a Tough series which I just love. You have to buy a case, of course and it takes a little getting used to, but I love mine. I also just invested in a new camera called a Paralenz which is a Dive camera developed FOR divers BY divers, but I would not recommend it at this time because it has a lot of bugs that need to be worked out, but if they can get them fixed, it will probably be THE dive camera of the future.