"an expensive HDMI cable will make NO difference in the quality of your picture OR sound"
http://boardsus.playstation.com/playstation/board/message?board.id=ps3&thread.id=828972&view=by_date_ascending&page=1
Most major electronics chain stores like Best Buy and Circuit City try to recoup the lost profit on TVs that get customers into the store by selling absurdly overpriced cables. These so called “Monster” cables are nothing special. Combine that with silly prices on TV mounts, TV stands, and so on, and you’ve just surrendered hundreds of dollars to them for profit.
http://www.macuser.com/video/apple_xtrememac_and_the_unlike.php?lsrc=murss