One tip I always hand out to rookies installing a home theater for the first time is to label every cable. It's actually the one tip I don't heed myself, mainly because it's typically impossible for me to simultaneously find masking tape and a Sharpie. That's why I completely adore this product from designer Micah Maraia, a cord-management product called Dotz.
Dotz are little plastic labels that easily slip onto cords. Each one is color-coded, plus it has a tiny picture of they type of device it's connected to. Simple, clever — and available! You can buy a set of 10 Dotz today for just $10. Next time you move, you'll be glad you did.