The more I monkey around with various lights, the more I find dynamo lights fit the bill in my case. That means a relatively steep initial investment (if you want quality stuff), but very little costs after that. I'm looking into replacing my summer utility bike's front wheel right now, depending on the dynohub it can be up to 250-300EUR. Maybe less if I build the wheel myself.

For rear I use blinkies such as the Planet Bike superflash.