I have a Cygolite (USB rechargeable) headlamp which I use for for touring, and occasionally in the city. It has three steady modes: bright, medium, and low; and a flashing mode.
I use the latter most of the time, and almost exclusively in daylight -- conspicuity helps to keep me safe. This flash is clearly visible from 400-500 metres away. (I learned this on a tour a few years ago.) On tour, I use it whenever I'm on roads with any amount of traffic.
Rarely do I ride at night on tour, or even in the city. When I do, I use the bright or medium steady light if there are no street lights, and the flashing mode when the road is well-lit.
I recharge the Cygolite as needed: on tour, about every 3 or 4 days from an Anker cache battery (recharged each day by my SON 28 dynahub/Sinewave charger setup). Recharging usually takes a few hours in the evening.
At home (in the city), I recharge the Cygolite from the mains, but I do so very rarely. (I have a standard AA-batt Knog headlight for my city city bike, but again, I don't ride much at night.)
My Cygolite is about 12 years old now. I think it has about 200 lumens; current models have 400 - 800. Cost me about $100, but it's been an excellent purchase. Only problem was that the translucent semi-soft plastic On/Off switch wore through a couple of years ago, but I fixed that with superglue.
Depending on how you use your bike, you could use both an LED light powered by the dynahub for nighttime use, and a flashing light (such as the Cygolite) for daytime use. If you did that on tour, you'd obviously need to recharge.
On balance, seems to me that the steady hub/LED light may be your best option. The only "but" I'd register is that a single steady light in daytime seems less effective than a flashing light in catching other road users' attention.
(For about a decade I rode a BMW airhead which had a triangular combination of a good headlight, plus two smaller LEDs mounted on the crash bars just in front of the cylinders. That worked exceptionally well, both for conspicuity and for my nighttime vision. Not really an option for cyclists.)
Hope that's useful -- good luck, and let us know how it works out.