I try very hard to be a stealthy camper or hiker and my gear and clothing choices definitely reflect that. My tents, backpack, bear bag, thermarest, sleeping bag, bandanas, hammock and rain coat are all green or brown.
This photo was taken from a campsite of mine that was fairly private and had plenty of tree and brush cover. I was a tenth of a mile away as the crow flies and I could see that obscene red shirt from through the trees when they first arrived and before they set up those crazy bright yellow tents.
If they would have blended in more I may have never known that they were there. Even though they were mostly out of earshot I still felt crowded because they stuck out with much too obvious colors. The only time I think yellow is an appropriate tent color is if you are camping in a tree with yellow foliage in the fall.... or winter camping in the snow for safety purposes.
In my own experience I have found dark blue and light blue to seemingly attract more bugs to the point that I never wear those colors anymore while hiking or backpacking. I agree with the light green, khaki, and tan as repellents because that is basically the only colors I wear backpacking or hiking now besides dark green and I just don't seem to be bit as much. I'm not sure about black enough to make a testimonial. I also refuse to wear bug spray because of their chemical nature. I don't like the idea of toxins being absorbed into my skin and I certainly don't like the idea of me polluting a stream when I go for a swim. Plus... that nasty DEET taste that lingers on your fingers while you are trying to eat some GORP just doesn't agree with me. I do get bit every now and then but unfortunately thats part of the outdoor challenge.