DS has one in his room because when he wakes up in the middle of the night the light helps him find what he needs and settle back down (or call out our names but he doesn't need the light for that =) Plus when we come stumbling in all bleary eyed at 3am it helps to have some light so we don't trip on stuff.
I experimented with several different lights (tyke light, regular wall outlet, touch lamp set to low) because DS can't stand it if he can see the source of the light. It really bothers him, I even have to keep the light on the wipe warmer facing away from him. What has worked really well for us are those blue night light bulbs. Apparently the blue light doesn't interfere with your ability to fall asleep (read it in an article somewhere). This has worked in both a regular wall light (when we travel) and in what we use at home (a salt lamp).
Salt Lamp
http://www.walmart.com/ip/Himalayan-...44440015902031 (sorry for the walmart link, thats just what popped up first in Google)
I found the Light Bulbs in a 2pack at the grocery/walmart/target etc in the light bulb section.
I should add that we keep the salt lamp on top of a tall dresser, so it's above his eye-level