Even with wireless technology now, I still use network cables here and there. I am writing this post right now on old computer in my basement running Ubuntu. Adding a wireless card into this machine is more trouble than it's worth.
You can save a lot money making your own cables compared to what they cost at Best Buy or other retailers. I've noticed they really go for the margins on cables, memory and other components.
I recently bought 100' feet of cable for about $20 and RJ-45/RJ-11 crimping tool will set you back another $20 or so. The only thing you need now is a pin-out map for the connector. Here are a few useful links:
RJ-45 pinouts and hints
Dux Computer Digest
