The logic of using the time honored traditional Red for right and Black for left to denote channels is obvious. I think Bunnyrabid was referring to WAF type issues so if you furniture sheme is light wood and your gear silver what color. I say White, Grey or Black always works well but don't use color as a criteria myself. If you have Dark wood try medium or dark blue. Red works nicely with Black gear. But these things only become necessary if there is a WAF. I can tell you that personally I don't particularily like garrish colors like bright purple or pink or plaids. (I have some Salmon colored PCs that have black woven drains YECCH!!)
What colors match for interconnects?
When I'm matching up interconnects with components, there is a strange little conundrum I sometimes encounter. The three colors; white, black & red. Or sometimes no colors, just left or right. Is there some simple rule of thumb for always selecting the right color or side? For example, is white, or left, always hot(pos)? What if your RCA posts are red & white, but your cables red & black?