I dig my Turbocat S10 (comes with a single light). I have the version with the CNCed cam clamp (pictured below) and small battery pack that mounts to the top tube with a velcro strap. It takes up very little space on the bars and the whole system can be cleanly removed from the bike in a few seconds.



My gf got the S15 on my recommendation and it is bright as ****. Hers came with a water bottle battery pack which won't work on a track frame. Mine was $90 shipped and hers was a little over $100 - both brand new on ebay.