I use a PB superflash out back on blink. The batteries last pretty much forever in blink mode. In front I have a dual halogen nightsun. 10 watts one side, 35 on the other. When riding in the dark I use both. Holy crap is it bright! I use a boat anchor SLA battery I mount on my rack. It is about 7 pounds. It will power the nightsun easily for 3 or 4 round trips which is about 6 hours run time. It might go quite a bit longer, but, deep cycling an SLA battery is a good way to kill it.

It is now sufficiently light enough to take this battery off which ought to make my hillclimbs a lot quicker.

So, if you don't mind the extra pounds, go with a big arse SLA battery and a halogen light.