Out daughter likes flashlights and often she will fall asleep with one on in her bed. We got one of those windup ones to save on batteries but it is to big for her and she doesn't like it. She loves the Mini Maglight that is much more her size. At some point she took it apart and lost the bulb, while I could have used the spare in the base I decided it is the perfect time to get the LED upgrade I saw at Walmart, It is from NiteIze and has 3 white LEDs in it.
It is a nice little kit, with a 3 LED bulb system and a replacement reflector. The new reflector is the hardest part to deal with, I needed a couple of pairs of pliers to unscrew the face of the Mini Maglite but the LEDs were a simple drop in replacement though it is polarized so if it doesn't light up when you pop it in you need to try it the other way. The LED is big enough that even if she pops it out it is big enough to find easily.
The light it produces is very bright and lasted for hours on old batteries. The flashlight itself gets rather warm after that much time but doesn't seem to be a problem.