Yes there is a big difference in the picture and or sound quality of cables. Everyone seems to have thier preference as do I. I would recommend going to your local hi-end audio video store as they will have a much better choice in quality cables and most will even allow you to take them home to try before you purchase. My favorite video cables to date are from a company in Arizona called Aural Symphonics, they are in the higher price range though but to me worth the investment.
Joe Kane (http://www.videoessentials.com) who is considered by many to be the video guru used to recommend a video cable made by beldon now Im not sure what hes recommending.
There is a big difference in cables but being more expensive does not gaurentee you a better picture, I would recommend you try different cables for yourself or read some reviews from the better magazines like Perfect Vision, Widescreen Review, Sterophile as they test the better gear and cables and are much more knowledgeable.
good luck
Kevin
I take it your tv does not have hdmi inputs ?