why do people feel the need to buy expensive cable

Calvinj - Once you spend $'s on most of those cables, you'll be Broke! ;)

I see cables priced well beyond what I've paid for my system. As a guy that has jammed cigarette butts into my ears due to lack of earplugs running a 120lb jackhammer I can honestly say, I'll never hear the difference. 

Quality cables are a must if you want to get the best out of your system. I've known people who upgraded their speakers or other components before upgrading the cabling in their system. At the very least, get cables that can make your system perform and you don't have to go broke. Belden 8402  mic cable is a good place to start cheap. Kimber also has inexpensive cables that are solid. High end systems need cables that will bring out the most, that's the only reason to spend big bucks on cables.

You have to see what a system can do first and that's down to the details. Placement, the room, speaker stands, cabling, power. All these things can sometimes make a system sound ten times better than it did because they were overlooked.