I have the eBay knockoff of one of these (which I think is just a knock off of another more expensive light) and it's fantastic! It is super bright and has a couple of different modes to suit you.

Amazon.com: MetroFlash Safety Zone Tail Light: Sports & Outdoors

here's the exact one I got...

New 2 LED Super Bright Cycling Bicycle Bike Safety Rear Tail Flashing Light Lamp | eBay

For a headlight I use this...

Amazon.com: 5000 Lumen 2x CREE XML U2 LED Cycling Bicycle Bike Light Lamp HeadLight Headlamp: Sports & Outdoors

It is very bright and has 3 brightness levels. I have only had it for a few weeks, but so far, so good. The connector between the battery and light is a little off (quality control issue), but it has not been an issue. For the price I don't think it can be beat. The battery pack is the thing hanging below the stem in the following picture. It comes in a canvass bag with a velcro strap to attach to a stem or toptube.