I like Walter's suggestion of the MYO RXP. It will take any AAs, keeps the batteries at the back of your head, which is likely to be under a hood, nice and warm, and is the rare regulated Petzl light.
I have an original MYO XP and it's my favorite "serious" headlamp, but this new one is better in every way. There's also the Myobelt if you prefer a remote battery, but the whole cord thing can become a bit much.
The Princeton Tec Apex is their equivalent model to the MYO XP, and also worth a good look.