Front lights are normally relatively easy things to buy – you just decide how much light and battery life you need, match this up with your budget, and away you go. Let's deal with these three critical variables first off: as the name suggests, you get up to 800 lumens; you also get an impressive battery life of up to 80 hours (2hrs if you use it on the full high beam); and it's all yours for $129.99.
Of course, 800 lumens of light will draw significant energy from the battery, but the seemingly measly 2-hour battery life is extended to 3.5 hours when used on the mid 400 lumen setting, and 8 hours when on the low, 200 lumen output. Throw in a 'hyper constant' mode, which runs constantly at 200 lumens with a strobe pulse of the full 800 lumens for 7 hours, and a flashing 200 lumen mode which extends life to a sizeable 80 hours, and you've got enough flexibility to customise what you need.
For a typical commute of up to an hour, you'll get away with using the full beans for both rides if maximum forward visibility is your thing; if you just want to be seen for long periods of time out on a club ride, the flashing mode will suffice, with a simple switch over to a constant setting easily done to get you home in the dark.
Read more at: http://road.cc/content/review/172440-cateye-volt-800-front-light
CatEye Volt 800 HL-EL471RC reviews
I use this light for night MTB and Cross rides it is the perfect brightness to define the trail without too much shadowing. It's also light enough to not be a burden on top of my helmet.
Used this as my main light for winter training on a local (familiar) trail. The light provides more than enough light, in a wide pattern with a decent spot.