The LED on my CNPS9500 is not too bright. You can view it in my setup if you'd like here:
http://www.techpowerup.com/gallery/288
Most of the light in may case is generated by my cathodes. I could take a picture of my system without the cathodes on if it would help you out. It'd give you an idea of how bright it actually is.
This is an ideal fan for over clocking and IMO, the best you can get before water cooling. I have my Pentium D 805 OC'd to 3.8 Ghz and I've had no temperature problems. Hope this helps you out man.