Belden 6a. Little pricey, but not boutique. Insulated and near impervious to interference. Connect to a network switch powered by a diy linear PS. You can find pcb's on diyaudio. That will firewall noise from your main. Make sure the switch is dedicated to your audio, and when you feel the Belden 6a, you'll know. Its stout.
Ethernet cable question
OK, at the risk of starting a big debate, I have just a dumb question: I see a lot of post talking about Supra 8 and Wireworld ethernet cables, so are you talking about cables making a direct run from your router? I have Cat 5 run throughout my house by me when our home was built 8 years ago. Everything is finished in the home and my sound room is not real close to where I have my network router/modem. So does the ethernet cable going from the wall to my Node 2i make any difference if inside the wall is only Cat5e?