I'm really unsure why a lot of 'audiophiles' claim not to be able to notice cable differences, as to me, the differences range from mildly obvious, to VERY obvious.
Resistance, Inductance and Capacitance of different cables vary; It stands to follow that so will the sound.
This is not to say that 'more expensive = better' - not at all. It's simply a matter of finding a cable that works well with YOUR PARTICULAR SETUP.
Example: Once upon a time, in my old setup at my old place, i was getting too much low end boom in my room, regardless of speaker placement. After describing the sound i was getting to my dealer and telling him what cable i was using, he suggested something that he thought would solve the problem.
The new cables, which did not cost any more than the older cables, were a much better match for my system. The bass was cleaned up and a veil was lifted from the midrange.
The difference was easily recognized by me and my girlfriend (who is not into audio gear at all).
Find what works for you... Hate to say it, but I sort of view cables as 'tone controls' (almost, but not really)...
Again, expensive cables do not necessarily mean 'better sounding' in your system.