I've bought a few B&M lights and a Philips light recently. They have all been excellent. I recommend B&M.

These lights are rated in Lux rather than lumens, making it impossible to compare. Their output is surprisingly weak, but the lights are extremely effective because the optics are so genius. It puts the light where you need it and not where you don't need it. It also casts the highest power far ahead, so the road looks to be painted with light.

Here's an excellent page of lights for sale, with explanations.