Bike lights are a minefield, the sheer quantity available is staggering, ranging from high powered units costing hundreds, to small emergency LED lights that cost pence, we try to offer a good selection of some of the best and most popular choices available. Whilst it can be confusing, deciding on a light to choose, try to decide on exactly what the light will be used for. You won't want a low power commuting light, for flying down your favourite local trail, likewise, a super high output race light isn't really the best thing for the daily commute. Id also always recommend carrying some of the low power led lights as emergency backup, these can come in handy in the event of battery failure of your main light, or perhaps getting caught out on a ride that went on longer than planned, they are really small and light and can be stuffed in your back pack until the need arrises
With regards to trail/xc/DH night riding, often people get caught up in the battle of "who has the most lumens". However, this is not the only factor to think about, whilst a good high lumen rating will certainly help, be aware that many of the cheaper high powered lights have a rating far higher than the output they actually give in reality! Having said that, all the lights you find in our "high power lights" page will give a massive amount of power suitable for most people reading this guide! One of the other factors to consider is "spread" (this refers to the spread of light given out) Whilst a 2000 lumen light is intensely bright, it means nothing if it is all concentrated on one small spot, also,"throw" of the light, how far "out" it actually reaches, a 2000 lumen light, offering a short throw and pinpoint spread will do you no favours when your hurtling down the trail!
Also worth thinking about is a second light, I still remember my first ever night outing to a trail centre, all setup, low power light on bars, off we went, however, at the first berm i came to it became apparent that the bars don't always "look" in the same direction as you! Thus a second light was swiftly purchased for helmet mounting! Personally i find the combination that suits me best, is a high powered light mounted centrally (or as near to central as possible)on the handlebars, (this light would generally have the better spread pattern) and a second high powered light mounted on my helmet, generally i prefer this to have slightly less spread than the bar mount, and also a slightly smaller unit, with battery pack located in camel-bak, as the weight can be noticed if you go for anything to big, likewise it can be more susceptible to branch strikes, so a shallow unit is a good idea.
When riding on the road there is so much more to think about than just yourself, especially at night, bikes on a country road in the dark, and drivers, in a rush to get home can be a recipe for disaster, making yourself visible to other road users is vital to ensuring your safety as a cyclist. typically, id say rear lights are the main concern, big bright lights are great, but its often a good idea to combine them with other lights, perhaps offering a different flash pattern, look for lights that have multiple attachment options, both frame bands/clamps, as well as clips for attaching to clothing/bags, id recommend at least one rear light on the bike, and another on your body/bag or helmet in case you have to get off for any reason. as for front lights, a medium power unit should give you ample light to see, and are often good coupled with a second smaller flashing unit, to help attract the attention of other road users pulling out from side streets and lanes. HiViz clothing is also another good addition to help you get seen when it matters!
Also take into account the battery, some will have a combined battery with the lamp unit, others have a separate battery pack, try to work out how long your light needs to last for the commute, and compare that with the lights figures, also think about charging, some units are USB rechargeable so ideal for plugging in at work, others may have a specific charger, or normal batteries.