cygolite seems like the way to go, and the 2w cygolite is not priced much more than the 1w Superflash.

Here is a linky:
http://www.rei.com/product/826583/cy...ear-bike-light

I keep a knog strapped on under my seat, and that one is fairly bright for night riding (25 lumens), and is worry proof. The bigger superflash is used more in spring/fall when I do more dusk/dawn riding and need the extra brightness/size.

Knog link:
http://www.rei.com/product/814761/kn...ear-bike-light