For an emergency kit, you probably want long-lasting light rather than bright-light. So don't get one of the new multi-watt wonders ... they will drain your battery too fast.

AA lights mihgt be a little large to fit in an Altoids tin. Even if they fit, they will take up quite a bit of precious space. You might want to think about AAA instead. Or even a flat battery type light like the Photon.

Gerber makes some nice, inexpensive, older technology lights (read: low light output but long lasting). Look at the Infinity (AA) or the Tempo (AAA). The Infinities, when they were made by CMG, were built like tanks. I own several. Now that Gerber bought CMG out I don't know about the build quality, but I assume it's at least still reasonable.

http://www.rockynational.com/1379_22-800..._White_LED.html

http://www.rockynational.com/2440_22-80107_Gerber_Tempo_Compact_LED_Flashlight_Metallic_Green.html

I have no idea if the specific merchant in the links above is any good. I just did a Google search on the lights and that one popped up. It shows pictures of the lights and a reasonable baseline on the price you might expect to pay. I am not recommending/dis-recommending this merchant - they are just an illustration.