I've used the Streamlight Clipmate w/green LEDs for several years. I like it because it can be used hands free. The light is more than adequate for walking in the dark. It also contains a headband mount. Battery life is excellent too. MI VHNTR
I have used the LED replacement bulbs for Maglites, which I found at Diamond-LED.com About 25 bucks for a HID/LED that provides tons of light without killing the batteries. They have many colors to choose from, I use Red for predator hunting.