If you're doing some hardcore hiking through the backcountry, you need a real flashlight with some power. But if you're traveling around the world with a light load and just need to find your way to the squat toilet outside now and then, you only need a basic beam of light. This little Maglite can be just the ticket, with only one AAA battery needed and a sweet retail price of $5.99.
The Maglite Solitaire is not much bigger than a cigarette and though it's metal and feels rugged, it weighs next to nothing. It has a keychain hookup that can also be used to hook it to something more substantial. Otherwise the worst drawback of this little torch would be how easy it would be for it to get lost in your pack.
This Maglite has the usual wide-to-spot adjustment and a bulb that can be replaced. It comes in blue, silver, red, and black. You can find it at the usual travel gear stores, but I got mine at Home Depot, for $5.99 plus tax.
Carry this in conjunction with a cheap MP3 player that also uses AAA batteries and you can use a portable battery charger to keep from adding more acid to the world's landfills and trash dumps.