I have a black diamond model that they don't make anymore, but the Icon is pretty close (mine has a much simpler bulb system)

http://www.bdel.com/gear/icon.php

one thing I would throw out, after a lot of use, is to get one with the third strap over your head, esp. for a BOB where you don't have to worry about size (as much) as when you carry it. I have used a two strap (head band style) and wasn't happy. The third band going over the top of your head seemed to stabilize it a lot for me.

ok ok, one more more thing is to consider what type of batteries are already in your BOB, if you don't have any AAA batteries or devices in there, that speaks to sticking with the AA

This all said, I think unless you are going to use it for extended periods of time, you can't go wrong with anything from princeton tec or Petzel