I think it's great that everyone here loves trying out cheaper lights and reviewing them for all of us - thanks!
However, I've been more than happy with the $50 I spent on my Fenix L2D. I was riding pretty fast last night, and in reading this post, I was reminded at the peace of mind I've had knowing that the Fenix lamps are rock-solid, stable, and extremely well built. I'd gladly pay $30+ for a uber-reliable light source than save $30 and find myself wondering if my light would go on a fast night ride.
Those ultrafires do look pretty sweet, though!