It worked OK, but it was barely sufficient. The light was the bottom end of what I considered safe for full-speed riding (20 watt MR16 halogen). I only had a charger at home, the battery was a 2.3 amp-hour sealed lead-acid, which don't do well in the cold, and the light was yellow and about gone by the time I got to work, so I'd be in bad shape if I had to stay late at work. It was OK on pavement, but a bit dicey on gravel. I put myself into some bad washboards a few times because I couldn't see more than about 25 feet ahead very well.
Of course, the holy grail for lights is an HID light. However, at $500 or so for a single headlight, I couldn't justify that.
Then, earlier this year, a company called Trail-Tech came out with a very inexpensive HID system for ORVs. No bike version, but they did have a basic lamp assembly that just needed power applied, do the attachment yourself; just over $100 for the lamp assembly. I studied up a bit and found that there's only one company making the HID lights and ballasts, and only one light in this size, so they're all the same, no matter who they're from (though a couple of companies have a low power mode, which I don't care about). With that much of an increase in safety, I couldn't really justify NOT getting this lamp. Also it should be more reliable than the old system, which got wonky on me a few times.
So a couple of weeks ago, I took the plunge. BatterySpace.com had seen the opportunity and picked up the Trail-Tech lights, plus they came out with their own water bottle batteries with charger. They offer either LiIon or NiMH packs. Since I will be using this mainly when it's pretty cold out, I choose the 4500 mAH NiMH. It's significanly heavier, but it does better than LiIon in the cold. Also it's a 14.4v pack, so it should be able to run the 12V headlight at full power until it's almost stone dead (the HID has an electronic ballast, so it should be able to regulate this fine).
The Trail-Tech comes in helmet mount or DIY chassis mount. IMHO helmet mount is really mainly good for off-road riding. Us road commuter types need the light mainly pointed straight ahead, and putting it lower means you get a better view of potholes etc. Keeping it on the handlebar also means not accidentally pointing it into the eyes of oncoming drivers. These things are BRIGHT - it supposedly puts out the same light as a 70 watt halogen.
Here's the Trail-Tech light and my mounting solution:
I also bought from SuperBrightLEDs.com a semi-truck taillight, which has 56 super-bright red LEDs, split mode tail/brake light. I plan to mount it in addition to the red truck marker reflector on the bike, with the tail light on constant, and a circuit to flash the brake brightness, strobe fashion. I haven't yet figured out exactly how I want to mount it, so for now I'm going to use the amber xenon strobe I used last year. This should be more than sufficient in combo with the marker reflector, and I may not wind up using the LED lamp.
I have details of the entire setup in an album here. The rear strobe and the switchbox are recycled from last year's setup.
UPDATE: Drill farther into the album for comparisons of my three lights.