How high end must your system be...

Three variables that haven't been mentioned but I think are significant:

1)Recording quality -- the greater the realism of the recording, the easier it will be to perceive differences in cables, as well as differences between other components in the system.

2)Cable length -- the greater the length the more likely it is that differences will be heard.

3)Component output impedance -- for interconnect cables, higher output impedance of the component driving the cable will increase some cable effects.

Regards,
-- Al

A fourth factor that I should have included in my previous post:

4)Speaker impedance characteristics and sensitivity -- everything else being equal, speaker cable differences will be increased if the speaker impedance and/or the speaker sensitivity are low, and/or if the variations of speaker impedance as a function of frequency are greater.

Some speakers are more "revealing" of differences in speaker cables not because they are necessarily better, but because they have these characteristics.

Regards,
-- Al