I like the suggestion of the 18650 Convoy S2, I recently bought two and I'm quite pleased with them. For output and spacing of light levels they cant be beat! Price? I forgot to mention the price they are one great bargain.
However for non-flashlight enthusiasts I strongly recommend an LED light based on a single AA cell. This is what I give away and FWIW I always give them away with a pack of disposable Lithium AA cells from Energizer. A year later I will send another package of Lithium's.
But, you could always go green and save them money by giving a pack of AA eneloops & Charger instead.
Neither AA eneloop nor the AA lithium disposable cells will leak and corrode to my knowledge and experience(so far) so these lights are safe bets to toss into a draw and be ready to go when needed.
Really an single AA cell based LED light is my ultimate lights. AA cells have become universal in popularity.
GOOD LED lights can often take any AA cell chemistry, alkaline disposables, NiMH rechargeables - like the eneloop, Lithium disposables and Lithium-ion rechargeables. All this increases the chance somewhere your going to be able to get one, single AA cell to power the light. NOTE: this does not apply to lights that take multiple cells, finding two that aren't from the same package is the start of corrosive leakage problem.