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Nah, I've been doing night CX with 300 lumens. Quality>quantity.
^This. I've been using some Philips light from Germany and while it's not insanely bright the optics and reflector is properly designed. Perfect vision on dark lanes. The best way I can describe it is that the light is relaxing and there's no hotspots. Unfortunately the light is heavy and the battery capacity could be better. Also the mount is a bit wobbly. Fine for a 2 hour dark spin though.
http://www.philips.co.uk/c-p/BF48L20BBLX1/led-bike-lights-saferide
If you're out in the country with no light what's the so ever. 600 lumen is about the minimum.
I've ordered this. But direct.
http://www.merlincycles.com/k20-high-powered-front-bike-light-86619.html
Bit of a faff with the separate battery. But should be nice now eternal darkness is setting in.