Try an update on the Cable Turtle, the flexible rubber XL Cable Organizer. It opens like a spool, so you can wrap thin to medium wires around its spindle; then it pops back into a slim, Jetson-esque pod.
For the Tangle of Cords Behind the Entertainment Unit...
Try Oxo Good Grips Cord and Cable Clip, an easy way to pin up one or more cords that won’t be seen. The clips snap open and shut for quick access, the rubber pads grip cords tightly, and there’s a hole for hanging.
Use Case Logic Cable Ties to create a color-coded system. Wrap matching-colored Velcro strips around the top and bottom ends of a cord or a bundle of related cords so you'll know at a glance which plug goes to the DVD player and which goes to the TV.
Use 1/4-inch-thin Cableyoyo. It holds six feet of cord, then releases it with the push of a button. Attach it to a desk or a computer with a stick-on pad (included), or pop it in your bag and take it to go.