Proper amp/receiver hookup

[GBMidge7]

Hey everyone, I have a few questions regarding my new amp and the appropriate cables for hooking it up. I have recently been making some major upgrades to the HT, including two new RTiA7s for my fronts, a CSiA6 for the center, and a new XPA-3 amp (Holy eff this thing is heavy, BTW!) to power them with. Even though I am not new to HT, I have never had an amp before, and since I have been spending the money to upgrade, I want to do it all right. My question is what would be the best cables to use to go from the receiver to the amp, the amp to the speakers, and the receiver to the surrounds that aren't powered by the amp? Right now I am just using 18 gauge speaker wire to go from the receiver to all the speakers, but I definitely want to use the best thing possible when I get the amp integrated. I am not looking to spend hundreds upon hundreds of dollars for cables, but I really do want to at least do better than regular old speaker wire. As you can see in my signature, I have a Yamaha RX-v663 which does have the appropriate outs to run to an amp. Thanks in advance for the help, guys.