My pick is the XP-G version of the S-Mini:
http://www.shiningbeam.com/servlet/t...sh-G-R5/Detail The XP-G model has more of a center-weighted beam than the XM-L, which is floody (I have one of each). The medium output is about the same as a Fenix L2D on Turbo, which will run a Fenix dead in about 1:45, versus over 6 hours for the S-Mini. At full power, it'll run about 2 hours to auto-shutdown. In a completely dark environment, I can use Medium.
Because the S-Mini doesn't have any flanges on its body, it can slip through a strap-type holder. If you get one, I recommend using a rubber band around it as well. It's very compact and lightweight, about 90 grams with the battery installed.