Flashlights and Batteries and Candles

The nice thing about candles is that they don't require any batteries. Downsides are yes they can be messy and there's the obvious fire hazard. Anything battery operated is of course limited by its battery life. If the power goes out you're not going to be able to recharge your re-chargeable gizmos from the grid so unless you've got a solar powered charger you're going to have to stock up on batteries. It would probably be a good idea to have both candles and battery powered light. Although when SHTF you may not want to do much after dark anyway to avoid unwanted attention. Light and noise discipline are good skills to hone.