I'm a novice to kayaking, but here's my opinion.
I wouldn't go kayaking at night, at least anywhere I expected much boat traffic. I'm in the coast guard aux, and I've just seen and heard of too many boating accidents at night. People just go too fast and don't watch where they are going. (That may depend on where you are, though. Our patrol area is Smith Mountain Lake, which is a local resort area.)
Now, that being said, if you are in an area where it's safer to be out at night, you should have lights on your boat. (I'm not sure if non-motorized boats are required to have lights, and my nav rules book is not handy, but I think it's foolish to go out at night without lights) For a kayak, I would use one white all around light.
Such as this one:
Be sure the pole is long enough that it sticks up above you head and is visible 360 degrees around.
My kayak is red and my lifejackets are red and orange, so I'm not too concerned about daytime visibility.
Yes, you should also carry a noise making device and an emergency strobe light on your person. Either of these can be used in your kayak, or if you fall out.
Stay safe!
-Adam