If for whatever reason you don't want a Rolex then take a look at the Blancpain Fifty Fathoms Bathyscaphe. It's water resistant to the usual 300m, is a more comfortable 43mm wide (and 13.40mm deep) and even includes a transparent case back, which is a feature less often found on dive watches; though, this may be due to the increased thickness they give a watches case, the perceived weakness that they give and the additional cost involved.
The dive watch is a type of watch that really encapsulates what it is to be a luxury watch. It's simultaneously a functional piece of specialist equipment, needing to survive the punishing environment of being dragged down deep underwater, while still telling the time: but, they are typically built to extravagant specifications, being water resistant to 10 or even 100 times deeper than people will actually dive down to in reality. Few people will ever test these dive watches to their full capabilities!