Network cards are no longer optional additions to your system. Adding a network card later may be the same price as the bundle but your clients should go ahead and purchase the network card with the system anyway.
Even the smallest offices now have cable Internet, wireless routers, and peer-to-peer networking. With these important changes network cards have become mandatory parts of computer systems. Most manufacturers include a network card automatically.
If the manufacturer installs the card, then everything will already be set up and properly configured so that your clients can immediately start using the card. Ethernet adapters are also an option, but if they fail, you will likely have to replace the motherboard if it's out of warranty.
Learn more about the benefits of adding network cards when you read the full article (link above).
Posted by Computer Consulting Kit