I'll second the LED headlight, I have one I have used frequently for over a year and still haven't replaced the batteries. For inside the tent I use a small AA flashlight with a biner that I hang from the ceiling of the tent.

K-mart ( and likely Walmart) also has a LED headlamp by Garrity that sells for $12 that works quite well. it has 3 LED's with HI-LO-Flash functions. I just used one of these to go on a 20 mile hike 1/2 of which was in the dark while raining and the light worked great