For headlights, there are two basic kinds: notice-me lights, and brighter lights that enable you to see in the dark.

I generally don't ride in really dark conditions, but often when I ride after work it will be near dark by the time I finish. So I just have some notice-me lights. But they are LED lights so they are very noticeable.

I have a basic Bontrager headlight (6 LED bulbs, I think) with two modes -- blinking and steady. Also a basic Bontrager tail light that can be used blinking or steady.

I also have small head and tail lights (1 LED each) that attach to my helmet with velcro straps.

In addition, I have these reflective ankle straps.

http://www.roadid.com/Common/LearnMore.aspx?PID=10

And I wear a white jersey and/or high-viz vest or jacket.

Years ago I used to go mountain biking at night. I had a helmet headlight for that. If I did lots of nighttime riding I would get another very bright helmet light, because they illuminate what you're looking at, not what the bike is pointed at.