You didn't specify if you needed lots of light, and whether or not you preferred spill or throw.
If you want a pocketable light with extreme run time(let's just say at least 40 hours), great flood beam for navigating and reading, and tough....then the Gerber Infinity Ultra
http://www.flashlightreviews.com/reviews/gerber_infinityultra.htm
will fill the bill. The IU is a highly regarded light, although many prefer the CMG
http://www.flashlightreviews.com/reviews/cmg_infinity_ultra.htm and early Gerber style to the new style. I have both and like both. Both offer about the same beam brightness and shape. The newer design will tailstand. The Infinity Ultra is available all over the Internet, and some retailers such as REI. You really should have one in your flashlight arsenal no matter what. They are essential as an emergency light and can be stored with a lithium battery for a decade or two. Incidentally, they run on a single AA battery of the Carbon Zinc, Alkaline, Ni-cad, Nimh or Lithium varieties.
The cost is about $20 or less, and unless you need lots of throw for spotting far away objects or blinding a bear, the IU is a great all purpose tool. No true flashaholic can exist without at least one of these.
There are some others in this class of light that are excellent as well. From Advancedmart.com, there is a AA "twisty".
http://www.flashlightreviews.com/reviews/amart_1aahw.htmThey refer to it as a keychain light, but its actually too large for that. It has more of a broad hotspot type beam, but is very useful, and its only about $12. The runtime is great, but nothing close to approaching the IU.
There are other highly regarded lights with good runtime that are a bit larger. One would be the River Rock 2xAAA from Target for $10. It produces a very nicely shaped beam with a hotspot and throw, and produces about 12 lumens @ .5w.
http://www.flashlightreviews.com/reviews/nuwai_tm-311h_2aaa.htm
These lights are manufactured by Nuwai, and other lights from Nuwai can be found @ Advancedmart.
http://store.advancedmart.com/fllipr.html
Another source for Nuwai is here:
http://www.j2ledflashlight.com/specials.html
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