Plugging your power cables into a surge protector will protect them from damage if there is a power surge. However, cables plugged into a surge protector at different angles can be unsightly. A surge protector cover has an opening for all of your power cables to enter at one spot to keep your installation looking neat.
Knowing what cord goes with what piece of equipment will make it easy to unplug one thing without accidentally shutting off something else. You can purchase specially designed cord labels at an electronics store, make your own with a label-maker, or wrap masking tape around the cord to make a tab that you can write on with a marker or pen.
When the wires from your entertainment center are cinched together with wire ties, this makes them look much neater. They also will be much easier to keep clean. You can purchase wire ties or clips that are designed for this, or use sturdy plastic ties that you already own. Be sure that the ties aren't so tight that they pinch the cables.
When power cables are bundled together with the cables that provide an audio or video signal, it can cause interference. If you notice interference after bundling your cables, separate the power cables from the signal cables. Try to keep these bundles of cables at least 3 inches apart, and if they must cross each other, it's best to have them do so at right angles.
If your entertainment center is not directly in front of a power outlet and the other outlets it needs to be connected to (such as a cable outlet or Internet jack), you will likely need to run those cables along the wall. Installing wire track will cover the cables and keep them from becoming an eyesore or getting snagged on other things.