What works for you, explain your setup and what you'd change?
You can't have a single light, and there's the factor between riding lights and map/nav lights
requirements -
light 1 - handlebar mounted,
a)external li-ion battery pack with cable connector, 220V charger
b)integrated system with rechargeable battery, 220V charger
c)AA powered handlebar mounted
d)hub dynamo
light 2 - helmet mount -
anything goes, but normally a headlamp ziptied to helmet.
light 3 -
the spare, actual light or just batteries?
I went from Dynamo to battery for simplicity and the battery doubles as bank to charge other electronics.
The bike light was the Magicshine Monteer 5000s, but would like to get the 8000 with remote control.
My headlight was the Petzl Actik with spare rechargeable battery.
https://www.petzl.com/INT/en/Sport/Headlamps/ACTIK
I used the Led Lensor MH7 as described by Chris, and was very happy with it.
I have used extreme lights on my bike for years but they are not robust enough - I am exploring other options especially after the battery issues I had this year.
My advice is to take a headlamp that is bright enough to use as main light source, should your bike light fail... because bike lights do fail/fall off... especially in cold, bush-wacking conditions of RASA! In the past I have always sworn by Black Diamond Icon as my headlamp of choice but I have recently changed to the lighter smaller Ledlensor MH7 and been very happy with it's performance. Very well designed pice of gear. Runs on 2x AA batteries. rechargeable (in light) or disposable. Lithium AA x2 will get you through a full night. I am even considering getting a second ledlensor MH7 to mount to handlbars and use as bike light also.