my experience so far differs from yours. looking to buy a budget amp for the S1 speakers after reading countless comments & searches, I got the Onkyo 9555 - positive review on Stereophile; good satisfied owners all around; positive comments from Paradigm's owners; and was almost half price of original retail price, can't go wrong, right? - wrong!
the 9555 is a fine amp compared to similar priced amps; pair it with similar priced speakers and you've got a pretty good system. use it with more expensive gear and it'd be wrong, I cannot think of a better term to describe it. it's not about power; the 9555 can drive the S1 to deafening levels, I enjoyed the sound, but wasn't quite happy about it, something wasn't right.
then I got the Anthem 225, and I was instantly blown away. everything that I wasn't quite happy about it's gone. it's perfect. I cannot tell you I glad I am I got this amp. I work hard for my money, £1500 is a lot of money to me, but I'd spend it again.
I think speakers are the most important factor in a system as the starting point. you need to find speakers that you're happy with first and proceed from there, but, in my experience, every other component is of equal importance; if you spend $2000 on a pair of speakers, and use a $500 amp to drive them it's just wrong. you can, but it wouldn't be right. using similar priced components is very important, IME. so much so that I've shipped today back the Emotiva CDP for a refund, I decided to save for a similar priced CDP.
as for the cables, I don't know if they make a difference or not, I may do a test once I get a chance, but the fact is I'm not prepared to take a chance to have the cable to be the wickest link in the system. I wouldn't spend thousands on cables, no way, but I wouldn't spend $10 either.
my 2c