For me cable management is having them out of the way of the hardware and airflow. While the pics setishock posted are great examples of a spic'n'span job of it I am not that picky.
I have an Antec 300 Illusion case. All the power cabling not in use is balled up in from of the PSU in the dead air space there. All the cable sin use are tucked to the side of the mobo for the most part with a couple routed behind. I tend to be in my case swapping things out fairly regularly so having everything cable-tied drove me nuts. Here's a pic of it (an old pic taken with a crappy phone with old hardware right after I moved to it). The moles sticking out is for the fan mounted in the side of the case.
