Finally a topic I can provide some good advice on
Stay away from non-case protected cameras if you are going to take it into the ocean, like the Olympus Tough or Sony D20... they just aren't made to last in those conditions, regardless of what the box says. I have seen several only last a few trips to the ocean.
I think the best buy for under water cameras right now is the Nikon P7000 with the Fantasea FP7000 housing. The P7000 is an older version of the newer Nikon P7100. There aren't many differences between the two. You can buy the P7000 and housing for $500, which is an amazing deal in my opinion.
Edit: of course this topic is a year old... and I had already responded, hah.