I have never heard a wit's worth of difference with PC's until I got the Shunyata Venom 3 power. The improvement is very audible, with more separation of the instruments and a wider soundstage. Well worth the $120. They have a pricey version of the Venom PC that is probably even more revealing.
I recent bought some Silnote ICs that are the best ever in my system for $199: the Morpheus Reference Series II IC. They are stunning IC's at their price point. I am going to order either their Poseidon GL or GS Reference PC's priced at $99 and $199, respectively. Silnote has an array of much more price cabling if you want to go up the food chain, but these PC might be as revealing as you like for way under a kilobuck. They have a demo period in which to audition them.