What bedroom paint color should I use?

If the walls have been painted before, you do not need a primer. Do use spackle to fill nail holes and any holes smaller than a dime. If there has been smoking in the room, wash the walls with a vinegar/water solution. Otherwise, wipe off the walls with a damp cloth to remove any dust or debris. If the walls are currently a dark or a deep tone of a color, you may want to use Kilz or a light colored paint first. Then, your new paint color will surely cover without the previous color bleeding through.