I had a Night Rider, which was fine, but I live in an area with no, or little streetlights and I don't see well in the dark. I now have a Bike Ray light. Really expensive, but I got it for half price from a site in the UK, free shipping. It has a high, low, and flashing setting, as did the Night Rider.
Word of caution. My son was using a more "be seen" type of light while riding home to his new house, which is in a more suburban location. He hit a pothole going down a hill and crashed, because he couldn't see. Don't be cheap here.