I want to go mountain biking at night, but don't want to spend too much money. What would be a good cheap light to use offroad?
Is the Cygolite Nite Rover any good or is it not a good brand?
I have tried the Nite Rider Digital Headtrip and it was bright enough and I liked it, but is expensive.
Do you want to be legal, or do you want to effectively navigate singletrack in the dark? If the latter, I would recommend making your own. Check out some battery sites and light sites. I'm no expert at all, but a team member hooked us all up for under 100$ each.
Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Niterider and Nitehawk make less expensive systems that can be easily adapted for off-road use. The Nite-hawk above sells the headlight assembly and wiring harnesses separately which you can use to make a killer semi-homemade system. I use NiMH batteries from RC cars that I wire in series to get a 14.4 V system to run a 20 W bulb. It's good for around 2 hours. If you were to go with a 10 W bulb you'd get 4 hours out of it. I would suggest that whatever you get you get 2 of them or at least carry a back up light. The Nitehawk emitter lights are good back up and almost as good as a 10W bulb (just narrower beamed).
The reason for this is twofold. First, you should make you helmet light your primary light so that you can see into corners. But having a light on the bar lets puts light lower and lets you see contrasts a bit better. Second, if you do break a light or blow a bulb you have something to see by to get you home. Go see Pee Wee's Big Adventure to see what happens if you are out in the woods all alone at night without a light
I just bought a Cygo-Light and I like it. It is not a super-duper model with the billet housing or anything. The niterider is nice but pricy. I got the Rover nimh xtra. It has 2 beams one is like a flood and one is like a spot, 6w and 10w for a max endurance of 6 hours.