I did a lot of research on headlamps before finally deciding on the Princeton Tec Apex. If you are looking for an extremely bright, long lasting, and versatile light then I think you will love the Apex. It is available in in 2 models. One uses 4-AAs and the other 2-CR123s as it's power source. The Apex Pro uses the CR123 batteries so it is a bit lighter. If you get the AA model, I recommend lithium batteries for your longest burn time.
Here are a couple of great review websites for headlamps. You can find my full review of the Apex on the Trailspace site.
http://www.trailspace.com/gear/lights/headlamp/
http://www.flashlightreviews.com/reviews_i...x_headlamps.htm
