I currently use this. Great power, built like a tank. Burns the battery quite fast though, but you recharge it to full capacity in one hour. Useless at 10mm coralscape if you're only using one. I've used it in night dives and I don't think I'll want for anything more out of it. I'm planning to buy another one soon.
I get a pretty good deal on that at our dive center trade rates, actually.
One question: what kind of beam angle do you get with it, and which lens have you used it with so far?