I do try to keep a low profile in general, maybe even more so outdoors. Blending in with the environment has always seemed like a good idea to me. Much easier to get closer to wildlife and basically create less of a signature, particularly if you know how to move quietly. To me, that makes for a more enjoyable experience in the woods because it lets me get closer to the natural environment.
A lot of my outdoor gear and clothing is military surplus but I do try to stay away from camo as much as possible. I guess G.I. Joe look is not quite to my taste. Besides, it makes you stand out in a somewhat more civilized setting, which defeats the whole idea of blending in in the first place.
I realize full well that my preference for olive drab or subdued colors in general poses a risk in case I ever get lost or need rescue. Hikermor makes a good point - having at least one article of clothing that stands out from the environment could be a big asset in a rescue situation. A bright red or orange plastic bag would work fine, too - and doubles as an emergency poncho or bivy bag.