The lights aren't really that bright, IMO. The noise of the fans might interfere with your sleep.
Is that true of any fans
I've heard that fans manufactured by Nexus aren't as loud. I've never used them, though. The noise is mainly due to the total amount of fans. You'll also have a CPU fan that, depending on the model, will create a fair amount of noise as well.
In a dark room the blue leds would actually dimmer then the typical nite light you have pugged in.