I am looking to purchase a camera (probably not a housing for an SLR) for scuba diving. Something not to expensive, probably less than 500. Would the GoPro Hero be a suitable choice, or the SeaLife DC1200?

There are some nice P&S cameras that can be used down to 10 meters.

Most of the underwater cameras specs will tell you how deep you can dive without damaging the camera

Many are only good to 3 meters, so you will have to spend some time researching

P&S cameras — http://www.dpreview.com/reviews/sidebyside.asp Olympus SW and Tough camera series as well as one Canon and a few Pentax cameras may fit your needs

GoPro Hero Surf can be used underwater up to 60 meters.

Shooting video, as you know, you will have to supply supplemental light since very little red light penetrates beyond a meter.