Basically you want a headlamp. You can always carry it in your hand when conditions warrant. It is much more difficult to carry a flashlight on your head. There are many situations where you will need both hands.

Dependability and reliability are extremely critical. The tint of the light and the number of lumens is not nearly so critical as the simple fact that it will produce light every time you activate it.

There are many fine models and makes out there. I really like my Zebralight headlamp and I have some very fine lights made by Fenix. There are many others.

Check out candlepower forums for an incredible amount of information by serious, dedicated nerds.