Every pilot needs a flashlight, and serious pilots carry two or three.
He reports that the pilot-designed NavAire is the best cockpit flashlight he's ever seen, while the tiny and inexpensive Photon II makes the perfect backup. In fact, a flashlight is so important that most serious pilots insist on having one or more backups. Also in the flight bag are plenty of spare AA and AAA alkaline batteries and a couple of spare krypton bulbs for the mini-mags. For preflight use, the best flashlight is the brightest and most powerful one you can reasonably carry. And for those ugly rainy-night preflights, a waterproof flashlight is a plus.