I'm surprised by how much some people dislike this camera. I don't know if it's operator error or unrealistic expectations on their part, but I've been very satisfied with it....
So that you can put my comments in context, here's my photo background: I'd consider myself a serious hobbyist. One of my university degrees is in studio arts, and for that degree I minored in photography. I even taught the B&W photo lab for a while. I use strictly nikon film SLRs, but I recently picked up a canon S3 for a digital pocket cam and I'm quite impressed with it.
I've previously used a Sea&Sea Motormarine IIEx with a YS60 strobe, but a few months ago (June) I got the DC500. It was a web special, $400 for camera and housing, new. I've used it to shoot some stills but much more for shooting video (about 20hrs so far). I use a 1gig card and have had no issues with freezing, PNY is the card make. You can get about one hour of video on a 1gig card, and since the battery will only run for about an hour of continuous recording they wash out in sync. I've been amazed at how well the video turns out, even at depths over a hundred feet using only ambient light (and I am not in the ocean) but I recognize it for what it is, a video journal to share with dive buddies, not a Wes Skiles production. It's extremely easy to use, although there has been a learning curve unique to my dive conditions. This summer the camera was going through a temp change of 40-50 degrees from surface to depth, and I was having horrible problems with lens fogging even with a dessicant (I found I had to pre-chill the camera in an ice box to avoid this shock cooling). It's small enough to pack along on any dive, and I've had a lot of fun testing its limits. The wide-angle lens is an essential add-on in my opinion. I've also had great success attaching the camera to a mini-tripod (ultra pod 2) and strapping this to two UK light cannons (10w HIDs) and shooting video on night dives. This is far from the world's greatest UW camera, but overall I'm quite pleased with it and would buy it again.