Three words: Petzl TacTikka Plus.
I would not want to fly at night without it. Not in your average spamcan with very poor (and often broken) cockpit lighting. Use the white & bright setting for the walkaround, then flip the red filter in place and reduce the brightness for in-cockpit use. Even if you're doing aerobatics at night you can't lose it and you have two hands free for flying and juggling maps.
(In contrast, on one IFR night lesson, the instructor forgot his own flashlight, borrowed my spare mini Maglite and managed to lose it no less than three times over a two-hour period. We managed to find it every time, but I don't want to think about what could happen if it would jam a cable somewhere. And at the end of the flight his drool from keeping it in his mouth was all over the place...
)
There's a slight disadvantage to using a red light in the cockpit though: some colors on the map will not be visible. I do not have experience with other colors filters but Petzl also does a model (TacTikka XP) which comes with various colors flip-on filters. YMMV.