Since I always seem to come back to this question, and always have such a difficult time finding it, I would like to start a thread that is specifically about the distance people keep each species of carnivorous plant they own from their grow lights (if you have any, of course).
Try to measure from the top of the plants, not the pots, and keep an average in mind. If you have any outliers that tend to skew your average either too close or too far away (like a very large plant, for example), mention it if you want, but still try to keep it simple and stick to the mode. Also, clearly humidity, temps, fans, and the kind of lights you are using are important, so mention this as well.
I was thinking it could be written something like this:
4 bulb T5 HO fixture / 3-tier open grow rack
Nepenthes (Highland): 23'' (plus 3 larger plants @ 17'') / 60% humidity / 70 degrees
Nepenthes (Lowland): 18'' / 80% humidity / 86 degrees
Pinguicula: 8'' / 40% humidity / 79 degrees
Drosera: 8'' / 40% humidity / 79 degrees
Cephalotus: 10'' / 40% humidity / 77 degrees
Heliamphora: none yet
I feel that if everyone can contribute some of their own measurements, it will make for a very nice average for others to reference. Once again, please be sure to mention the type of lights you use and whether or not your rack is open or not.
Lastly, if there already is a thread exactly like this, I apologize for my inability to conduct a thorough search of my own. I once encountered a few posts where people did mention distance, but these are buried somewhere deep in the search feature and I haven't been able to locate them since (I'm sure someone will be compelled to find them and send me a link ) Nonetheless, I think this was needed.
Anyway, please contribute!