+1 on the 4 Sevens Quark Mini 123, but only b/c I got the warm-tint LED. For backcountry use, the warm tint is soooo much better at differentiating natural color tones. It's like having x-ray vision: where the gray/brown rocks end and the gray/brown trail begins is very clear. Also, slippery leaves are contrasted well against non-slippery rocks. (I compared the Mini to my Fenix L1D, and the cool white LED in the L1D made everything looked washed-out.) Think of the warm tint as the benefit of holding a light at hip-height (vs. on your head) times 2.
I use Tenergy 900 ma rechargeables in both the Mini 123 and SteriPen Adventurer; you can get a recharging set with 4 batts. on Amazon.com for about $30. Figure half the runtime with a rechargeable (which is normal for Li-Ion), one battery can last 3-4 days in summer (~3 hrs on low, ~1 hr on medium, ~1/2 hr on high, per day). Weight with one battery is 1.25 oz.
One thing I don't like about the Mini is it tends to skip levels (low to high, when I just wanted medium). I only wish there was a headlamp version.