In the last writing, halogen was still a "buzz word", and things like NiteRider's old Digital Headtrip were making headlines. Fifteen watts of halogen on your helmet was amazing stuff - but right as Halogen was peaking in bicycle circles, it seemed that HID (high-intensity discharge) was beginning to stir things up. Ridiculously expensive, but insanely bright, HID lights were king of the trails and streets for a few good years - but ultimately proved sensitive to vibrations, power-hungry, and bulbs were expensive. Right about then, LEDs started showing up. At first, they were near comical and strictly "be seen" lights. A mainstay of taillight products for years, it initially seemed the emitters just weren't up to the job of being anything but power-friendly position-marking lights. Anemic beams, diffuse, with confusing colors - it was sometimes downright scary to ride with one... I remember trialing several, and sticking with my trusty halogen generator system. With the correct optics, even as brighter Halogen battery lights came available and HID started to make shadows of anyone else's lights, the German optics of the old-school Bisy and Busch+Muller halogen systems - even at a measly 3W - still put lots of very use-able light on the road.
Looking back, only a couple years later, I can't believe some of the stuff I used to "be able to see with". By comparison to what's available today, they all seem silly - even the old top-dollar halogen generator lights, and big 30W halogen battery systems. Even HID lights, once thought un-beatable, have been completely dethroned by LEDs in the areas of brightness, beam pattern, run-time, weight, efficiency, and cost. Today, assuming you can even FIND anything besides it on the bike store shelves, if you aren't running LED lighting - you probably aren't riding at night.
I was most excited, to be honest, when LED technology finally arrived for the generator-hub crowd. I purchased my generator system at a time when halogen was the only thing available - and it was still expensive. Even a 5W halogen rechargeable headlight would cost over $100, and would have a run time that would have barely gotten me home. I instead was using an old Cateye "Halogen II" handlebar mounted light, which used a micro-sized halogen bulb and produced 2.4W of output. The optics were descent, and you'd get a usable beam of light projected onto the road that would serve you up to about 15-16 MPH. Downhills were experiments in faith. Yet, for years, that light got me home - night after night. With LR3 (AA) drycell rechargeable technology still being a bit "fringe" and also expensive, however, I was running through disposable alkaline cells at the rate of a 4-pack every fourth commute day. On some well-lit roads, I'd ride by streetlight - switching the light off completely to save battery. When I finally ponied up for a generator system, it was with the knowledge that it would pay for itself in disposable AA's in only a year. After almost TEN years of use now, it's safe to say that it has done that easily. I had no complaints about the generator system's halogen beam for years - knowing I never had to plug anything in or replace cells opened up worlds of possibilities, saved money and time, and made things like long night rides a worry-free affair. It wasn't until LED lights started showing up that I developed "lumen-envy", but LED technology combined with improved optics proved to be a perfect marriage to the existing generator systems - and soon, I was part of the LED party, too.
However, with run-times exceeding DAYS instead of hours in some extreme cases, the same possibilities that the generator system opened up ten years ago are available to anyone for often a fraction the costs - and it can easily be moved from bike-to-bike... especially in contrast to generator systems, bikes across many genres and wheel-sizes in your stable. On that note, you don't even have to buy a "bicycle-specific" light to enjoy the benefits of night-time riding. Any purchase, especially in tough economic times, should be smart -- and, that brings up the notion of multi-tasking products. Where it may not make good financial sense to purchase a "bicycle light", one can often make the argument for a good LED flashlight... and now, usually for far less money than a bicycle-specific light, you have a flashlight for around the house, the campsite, the garage, AND the bike. Zip-ties, an old length of inner-tube, a silicon arm-bracelet for your favorite cause, duct tape, or some combination of ingenuity and old reflector mounts or clamps can easily adapt any flashlight or torch to your handlebars, and you're off into the darkness. A recent post from the Kansas Cyclist touches on this perfectly, and I have seen Noah from KC-Bike ride many of our night-time events with a smartly purposed LED MagLite... and from any angle, these lights are just as bright and effective as any "bike specific" system.
The problem, often, is choice. You can have LED lights that are bike or non-bike specific and do a fantastic job lighting the road and rendering you conspicuous to motorists around you - but where to begin?? Pick your price point, and enjoy -- the tech will amaze you as much as the output of these latest emitters will. It would be an exhaustive effort for this author to try and keep step with everything the market has to bear currently - but there are a myriad of resources to research these things: Candlepower Forums is a great source if you really want to geek-out - especially for the still-very-relevant homebrew crowd, where dime-to-dime, you can probably outshine most commercial offerings with some elbow grease and a soldering iron. MY personal favorites are, in no particular order, are listed as links below - based on lights I've either owned or had the pleasure of messing around with for a weekend:
I will remind the reader that this is very much from a "pick your price" perspective.
The first two on the list, specifically, know no boundaries when it comes to power output, run-time, and low-weight racing systems for serious off-road 12/24-hour competitions, and the prices reflect that passion. Sticker shock will be a factor... but, taking advantage of these companies expertise at their lower price points does not disappoint, and you can find a seriously well-made commuter light.
Still, also keep in mind - just like Kansas Cyclist touches on, and from what I've seen from Noah's MagLite set-up - there is no reason to spend hundreds unless you demand a specific, bicycle solution - especially if you seldom venture off-road. From a few hundred feet away the difference between the beam of a $10 LED flashlight and a $200 LED bicycle-light can appear almost indiscernible. From the saddle, however, it will depend on terrain, your individual eyesight, and your intent. If nothing else, this list of links will demonstrate both the state of the art and what's possible at multiple price levels.
Finally - know your numbers: like anything sold these days, marketing is an important tool. Read this. Lumens, candlepower, LUX -- they can be confusing. More can be better, but not always, and it depends greatly on how it's measured. So, balanced against price and your goals - be sure you know what you're buying. Optics can play a big part in this, and it's especially prevalent at LOWER price points - so, if you are looking at a $30.00 bike light that claims 1,000 lumens, be sceptical. Is there spill? Will you be able to see 2 feet to either side? What's the run time? There's no free lunch - so demand good specs when shopping!
Remember - ride safely: bright lights are not a replacement for responsible riding, and good reflective gear so you remain visible - even when your 4,000 Lumen monster is pointed the other direction... and that's possibly no exaggeration: at this writing, there are people testing new systems for the 2012 and 2013 season, some exceeding 4,000 lumens. Un-real!
Enjoy, and see you after dark!
Busch+Muller (generator lights)
Supernova (generator lights)