After searching for ages for the most recommended lights and trying a few out for myself ive settled on a twin XML, as reviewed and sold by torchythebatteryboy.
They have a great spread and don't appear to suffer at all with overheating issues like other 'wonder lights' ive come across (MJ-872 is worst culprit). They also have a very impressive throw. I've seen around 2h45min+ on (mainly) full mean so plenty of burn time too.
You can also ditch the rubbish rubber band type bar mount kit and easily adapt a universal Hope bar mount kit to fit, which gives a rock solid mounting to your bar.
Bear in mind these pics were taken in pitch darkness, you can see how good the throw is on my neighbours wall!
These can be found for as little as £99, I really don't think anything betters it for value, that is, for true fast speed reliable off road night riding. Coupled with an Exposure Diablo on my helmet, im really happy with my night ride set up.