Heres my two pence;

I do not work for and am not an agent for QED but this report is excellent

[Link: qed.co.uk]

Most of my customers want a cable that "looks" like it does the buisness.They just want hifi jewellery.

cheap cables are often very poorly constucted so are most free in the box cables it makes sense to upgrade to sensible well constructed reasonably priced cables.

one dealer (Russ Andrews) suggests you spend 80% of your budget on cables!(guess what they sell) My opinion is that is just silly.
I would definately have a £400 DVD player with a £100 cable rather than a £100 DVD player with a £400 lead.

Gilbert Briggs was the original engineer at Wharfedale speakers and his phrase "the more you open the window the more muck blows in" is quite true .Better equipment does reveal more and a cables effect can be heard and seen .But on cheap equipment it cant make a silk purse out of a pigs ear.Thats what most customers want and the cable companys suggest they do.

The Optical cable as mentioned on other posts in my opinion is the biggest cable con. We have become used to thicker is better but optical fibres have to be narrow enough to keep the angles below the critical angle for total internal reflections to occur.so most of the thickness on expensive optical cables is just plastic covering.I have NEVER heard ANY difference in ANY optical cable ever.

bob