I am a commuter but have ridden for recreation at night as well. I bought the Cygolite Dual Cross (Li-ion) from pricepoint. The light is awesome and the batt is small and lasts >3 hours on the brightest setting.
Try the American River bike trail at night. You might want a small helmet light too if you're really flying around the tighter turns. My rear light is a cheapo, but its bright.