You could get some dynamo lights.
Maybe about £80 for a wheel with a Shimano dynamo hub, and £60 for a B&M IQ Cyo (plus about £10 for a rear light if you want).
Plenty bright enough for riding on unlit roads, decent side visibility, and no worries about batteries.
This is what I have. A Shimano Dynamo hub and a B&M light. I have the IQ fly, the old 50% less bright model of the IQ Cyo, and that is jolly bright, enough for unlit roads. If you turn the bike upside down and turn the wheel with the lights on, you can feel a very tiny bit of drag, but you absolutely don’t notice it while riding – mine has a light sensor which makes the light turn on when it gets dark, and there is no way you can tell that it has turned on.
I used to use lumicycles, both halogen, and a custom triple LED light, and this is a million times more convenient – no remembering to charge, never runs out, is always there on the bike for things like in summer when you stay out late and end up needing lights. Seriously, there is absolutely nothing that is as good for commuting. It is as convenient as car headlights, just always there, and low maintenance too – I put mine on the bike in September 2008, and set the switch to light sensor mode so it turns on when it is dark. I don’t think I’ve touched them since.
Dynamos have a bad reputation due to those old ones that used to go onto the tyre and add massive drag to your riding, which were combined with rubbish bulb lights that weren’t bright enough to ride with. Nowadays, with low drag dynamo hubs combined with very bright and low energy LED lights, they are just perfect. I’d even consider one of the fancier triple LED ones for my mountain bike if I had a large bit of money spare (some 24 hour solo racers have used them).