So many great options. I'd probably suggest a SWM D40a or the new XinTD X3 running eneloops. With no specified requirements I'd have to stick with the smaller lights for all around use and carry. Maybe a ZL SC52. Too hard for a flashaholic to list just one perfect light.
Sunwayman D40A. Its got most of the modes covered.
S6330.
Small size easy to carry around
Output cover from 0.09 lumens to 2400 lumens
Three independent circuits accepting 3 x 18650s
The goal of the light is to be for all roles and any situation, or as many as possible right?
The problem is in some situations you need to allow others to handle the light.
Ergo the light needs to be idiot proof, and not capable of frying itself.
The nightmare scenario with the Balder HD1 is someone takes it, turns it on on high, and leaves it to run... if there is a lithium battery in there, I'd be kind of worried.
Btw, the SC52 is brighter, and also very small, iirc even smaller.
The reason I'm so critical of the Balder is I had it turn on by accident, and get ridiculously hot. By the time I noticed, I had to pull over in order to get out of the car, and get the light out of my pocket... it was too hot to handle but I didn't feel the heat until it was almost too late (there was a microfiber cloth, and the fabric of the pocket between my leg and the light).
Don't get me wrong, it's a nice enough AA flashlight, but imho it's dangerous with a 14500.
I’d recomend Solarforce L2p together with Neutral White - XM-L2 T4 5B1 (80CRI Min.) 4-mode drop-in from intl-outdoor.
Jetbeam Jet III M, possibly the toughest light on the planet. Nice size, adequate output.
The most versatile, easiest to operate, reasonably priced torch for quite everyone; taking generic off-the-shelf cells with no complicated chemistry; backed by a warranty; suitable for women, men and even children? Which can be taken on any airplane, a boat, or in a car, which is well-made and even waterproof, and easily replaced in case of accidental loss?
Mini-M@glite LED pro plus.
Sunwayman V10R Ti with a Nitecore 16340.
If you had to recommend ONE flashlight, what would it be?
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One of mine
Sorry, couldn't resist...
Given no specific requirements, my answer would depend on who was asking. Probably an EDC-style light, but beyond that it would depend on what the person might reasonably be able to EDC. For each person who comes to mind, I picture them with a different light.
At one end of the spectrum, I’d give them a 1xAAA light such as an iTP A3 EOS or Olight i3 or Olight i3S or Tank007 E09 or Fenix LD01 R4 or Klarus MiX6 or Preon P0. Depends on what the person can reasonably carry, and how, and how light-sensitive they are. This sort of option would be mostly for people who don’t like to carry much, or who might want it on their keychain or perhaps even worn as a necklace.
At the other end of the spectrum, I might suggest a XinTD C8 V4, but only for people who need to see pretty far and don’t mind carrying something a bit large. Or a Nitecore SRT7 if they’re a feature junkie. Or something even bigger, if I know they mostly want something impressive and powerful — SRK, TM26, TK75, TN31, etc.
In the more general case, I’d suggest something relatively small and versatile… ZL H51, ZL SC52, JB RRT01, or L3 L10-219. Perhaps a ZL SC600mkII if they want something bigger and brighter and longer-lasting. The specific choice here would depend on their personal traits.
My personal choice would be the ZL H51c or plain H51 (or H51d or H52d if they ever make one). Although a little awkward at times, it’s the most versatile overall… and I don’t mind the complexity or ugly appearance.
But I don’t like to use just one. I carry a few for different purposes.
Sipik 68 is the best flashlight ever ! Very cheap, bright, small, 1 mode, belt clip, use AA and flood to throw beam. Bright enough with alkaline AA for daily home use.
This is exceedingly difficult to pick just one light!
I think I’d have to go with a 6P (or clone), since it is so versatile with the right drop in. It’s large enough to have decent runtime for most activities, but small enough to be carried quite easily. Not an “EDC” light, but the perfect general purpose light, which I think fits the original question.
In reality I’d probably bring 13 different lights however, just to be safe! :bigsmile:
My next mod. It will always be the best one yet. 
Tbh though, a single 18650 with 4 cc modes and hidden blinkies and a few extra cells would be a great emergency light.
I would tell guys to quit spending money on stock production lights and just buy a vinhnguyen54 de-domed XM-L2 TN31 driven at 6.5 amps. No stock production flashlight including most HID spotlights you will buy now or probably even in the next year or so will touch it for throw.
Trustfire TR-J12, high output, reliable, cheap and good balance of flood and throw
One flashlight - For everything ... And everyone ..
Jetbeam PA40
Otherwise I would ask a few questions like
1/ What battery ?
2/ Where is the flashlight going to be ? ( At home , in your pocket , on your key chain )
Just for starters ....
Sending one of my kids to Alaska for two weeks of an adventure camp. He has a decent headlamp but decided he needs to know more about what is out there lurking in the dense alder, and it gets dark now at night where he is…
So, new choice for him. Ultrafire 501, w Keepower or Panasonic protected batteries and a new XML2 5 mode drop in wrapped in foil. He knows to shut off or power down when it gets too hot and I feel better that the woods are a bit less dark for him. And if it gets lost in the backwoods tangle or dropped into the sea from the kayak, not a huge deal.
Last week it would have been my new SF K-3, but a clever and resourceful fellow BLF’r has plans for it in the meantime!
Mine Surefire U2 MC-E.
Built like tank, can run on cr123 and 18650.
Mike
lucky kid!
I would have to say right now, if i were to recommend only one flashlight to a non flashaholic, it would be the xintd x3. have them run it on either nimh or lithium primaries. if they want more, you could always train them on li-ion safety and order up some 26650s and a charger for them.
there are a few things i would have changed if i could. would have made the battery tube a few mm longer to fit a wider range of cells, and would have made the tube a bit wider for a 32650