what digital camera are you useing?

[divbum]

I use the Sony PC-330 video camera.  The mini DV format is a small package with good digtial capture results.  You can take stills and video on the fly, or grab stills off the video later ( at a lower res).  It is in a Gates housings, twin 24 watt Halcyon HID lights, and as Jon mentioned a good wide angle lense.  I use a filter for green water it is magenta..ish.
Good luck.  Also Reef master is putting out a new lower cost digtal soon which I have sen guys get really nice results with up to 250'.