Canister lights?

[Chris H]

You likely can't go wrong with a light from any of the major players.  I would make sure there aren't signs of flooding or abuse, but other than that it is tough to say.  As was mentioned earlier, I had some issues with a Dive Rite 10W slimline.  Their customer service is excellent, but it is no fun to have your primary light go of and on at will in 200ft of water, and doing a night dive on the Milwaukee with a Scout light is no fun either. (Although we still laugh a lot about that one)  I have since switched to a Halcyon 9/18, and love the light.  Like Todd mentioned, the 18W lights are great for signaling in non dark conditions where something less is not visible.  If you are spending the money,  get at least an 18W HID.  There have recently been some posted on the Decostop for $500-$700.  Which I think is a pretty good deal.  Some will tell you the Welch Allen bulbs are too fragile.  I haven't had any problems with mine.  I don't pound nails with it, but you shouldn't need to.  One other thing to consider is what your buddies are using.  If they all have lesser lights, the benefits of the 18+ may not be benefits.