I use a combination of bar and helmet mount at night.
Light & Motion Vis 360+ has both a front facing 250 lumen LED and a rear facing red pulse light. This is my favorite light. A piece of velcro usually secures the coil cord to the helmet so it doesn't flap around. If I had to choose one light only this would be it.
For the bar I use a Light & Motion Urban 800 Fast Charge. High, low and daytime pulse if I chose to use it during the day.
An Axiom Pulse 60 is always attached at the seat post clamp area on one of the bikes. During the day it flashes but is on steady when used at night with the helmet mount lights above.
I also have an Blackburn white LED which I mount below the stem so that it turns with the bars. I don't always use this light. It is a flasher during the day if I am riding in areas where significant traffic is expected. It is also a backup light on longer night rides and then I might not even use it, or might click it on steady for intersections or heavier traffic areas.
I also use those reflective ankle bands at night.
It all cost a few dollars but You have to be in a coma to claim that you didn't see me. It opens up a whole new arena for riding - warm summer nights on empty country roads.
-Tim-