The mistake most people make is to fit a light to see with. But you also need to consider being seen. A Topeak Whitelite offers little light to see by (whilst riding) but can be seen from a long way away.
The Extreme Deal lights give great light to see with.
Personally, I use four different lights on the front whilst commuting. Two are flashing LED's that last 100s of hours, one is a steady/constant LED and I use the ExD one when I need to illuminate the road.
As for rear lights I have three Blackburn Mars 3 lights.
I also have reflectors and use Schwalbe Marathon Plus tyres that have reflective side walls.