To the OP: What do you want the light to do, and how do you want to carry it? What kind of BC are you using, and what's your budget?
I was appalled as a new diver at how much dive lights cost. A set of lights with a big one, a middle-sized one and a small one was almost $200!
My last light cost me $1500.
That gives you an idea of what the spectrum is. Lights vary in power, burn time, degree of focus, and whether they require to be held in the hand. If you are doing only an occasional night dive in tropical water, a fairly small, hand-held light may suffice. If you are looking for something for Southern California, you are going to want a more powerful light, and possibly with more intense focus, especially if you end up using it for communication as well as for looking into and under things.
Give us a bit more information, and we can give you some options for lights that will work for your gear and your needs.