I'm pretty much only a trout fisherman. Not that I won't fish for other fish, just what I like the most right now. That being the case, the flies I'm tying are trout flies.

JC's article on what fish see also had a hand in my posting the color question. Also, as a couple of you have noted, when viewed from underwater, a dry-fly is backlit.. black, for all intents and purposes. I can definitely see where color would make a difference under various circumstances, different fish, water clarity. But when I look at a pattern that calls for cream hackle I can't imagine that substituting the white hackle I have on-hand wouldn't work. Or a dark ginger for brown..etc, etc. Not to mention, at this point, my bank account wouldn't survive an effort to acquire the rainbow selection of hackle available. I imagine this is one of the issues that keeps new or younger fisher-people from either tying their own flies or trying fly-fishing altogether. The initial out-lay for a new tier can be daunting if you don't keep your head on straight or determine you need EVERYthing in the store to catch fish on your tied flies.