You might also check out the Planet Bike Alias. Performance has it on sale for $99.99 right now, but you can probably find some coupon codes on the site here to get it even lower. I think I paid about $85 for mine, a year ago. It's sold as a "10W," but all of them I've seen actually came with 15W bulbs. Very thoughtfully designed. One nice feature not even mentioned in their ad copy is that they built it to give diffuse red glow from the bottom of the housing. It's not a substitute for a taillight, but it does make you hands, handlebars and part of your front wheel visible in the dark to drivers coming around from the rear.