Know your gear
You're getting ready for data rates of 100 Mbps and up. You'll have to install and maybe build what seems like miles of Category 5 cable for each of several systems. And you know what's coming - printing and attaching labels to every single cable so that people can figure out which cables are carrying what. Why not reduce the uncertainty (and cut down on the labeling) by using different colors? Unlike labels, the colors provide visual cues for a cable's function all along its length, and they make cables stand out from others in the same nest or bundle.