I use the Petzl TacTikka XP which is a 1W LED bulb, can be worn head-mount, or with the ADAPT kit, can connect to helmet, MOLLE, shirt, belt or pocket and can be swivelled up, down, left right and 360 degree rotation.
http://en.petzl.com/petzl/LampesProduits?Produit=606
Adapt kit:
http://en.petzl.com/petzl/LampesProduits?Produit=562
The light can also quickly switch from a spot to a flood (via a built in diffuser) which can be quickly swapped from red, green, blue, or white with different output levels (high, medium, low, blink).
Also has a built in battery level indicator.
Originally read about this light on Military Morons, and has become my most-used flash light. See his review on it:
http://www.militarymorons.com/equipm...umination.html