DoItYourself.com has a great article on wiring your home for the 21st Century. The article mentions:

If you're just beginning to plan your new house, you may not even know that you need the gray box and the structured wiring network, though you may be well aware that the gizmos you have nowcomputers, phones, televisions, and VCR's or DVD'scan be a cause of information gridlock and familial discord. For example, in the evening family members are frequently nagging the person on the computer to get off so they can check their e-mail. Or, both phone and e-mail are tied up because your teenager is Instant Messaging six or seven friends, while yakking to an eighth on the phone.

Overall, a great article that gives you some important things to consider before you build your home.