Modern lights are so, so good. Every techy advancement has shot them forward a bunch, and even the worst modern lights are better than anything pa or grampa used up to even 2012. Two ways to go: Rechargeable LEDs, or hub-generator (dynamo) kind. Most riders have both, for different bikes.
Rechargeables are tiny, inexpensive, and bright enough for all but the fastest, darkest rides on the twistiest roads and trails. The ones we offer are made in California by Cygolite, and mount anywhere on your bike in 1 second, come off as fast, so you can takem with you. Dynamo lights run off hub-generated electricity, so you never run out of light. The brightest of them turn night to day, but they cost more and ask that you be up to the minimal wiring challenges. Instructions included!