I am also looking for a camera (including case) for 300$ or less. The cameras listed above are interesting but I think I would be too scared of an accident and losing the camera (being a new diver I want something easy to operate and not have to worry about flooding, etc). What about the SL320 from sealife (same price range)?
http://www.sealife-cameras.com/cameras/reefmaster_mini.html
It seems the risk of losing the camera from a flood would be much lower and they have the possibility to add a wide angle lens
http://www.adorama.com/SLFMWASL320.html
Anyone can tell if the image quality of this type of camera would be as good as a camera+case? Is it possible to add an external flash (not something I'll do at first but I'd like to keep the options open) if using a camera+case?