A word of caution: if you do NOT use your flashlight often, then DO NOT buy a rechargeable!
NiCd's cannot hold a full charge for extended periods of time, and if you leave a charged flashlight on your shelf for a month, you will find it almost empty when you will need it in an emergency. 0n the other hand, leaving it on "trickle charge" constantly will ruin the batteries' performance.
Rechargeables are great if you use your flashlight a lot, but for occasional emergency use, get a good quality alkaline or lithium cell flashlight that will not let you down when it matters the most.