It would depend on where you ride and for what purposes.

I ride early am - like this am - on our trail system in the dark at slow speeds. I have 2 bikes equipped with lights. One has two $10 53 LED lights that show the trail like with a flood light - just fine and show the deer and rabbits. But, I would in no way ride on the road. The other has two Cateyes - much more focused, but don't have a "flood" caracity - they were about $35. Again, I would not use these for riding in traffic, but they do OK on the trail.

An important factor is to let others see you. The other morning, another rider approached with no lights - even though it was lightening a bit, I could not see him until he was quite close. I also have rear lights.