There's tons of solutions for hiding the cords that tangle behind your computer desk or media center (We happen to favor the DIY rain gutter method, ourselves). But some wires, like headphones and peripheral cords, just have to be in plain sight...
But here's an easy solution for keeping those extra-long cords tidy (Who needs a five-foot long headphone cord anyway?)—tie a quick chain sinnet (or chain braid, daisy chain, or monkey braid) into your cable to shorten it and keep it neat:
You creating a chain sinnet by making a loop at the base of your cord, then pull the remaining cord into each new loop. Be sure to keep your loops loose to avoid damaging the cord.
More detailed instructions, plus a video, can be found here.
Images from tomas carrillo at Flickr with a Creative Commons license.