Ethernet Wiring

Some of the best money I've ever spent on my system was to pay pros to install both ethernet cabling for streaming and before that coax for my FM antennas and cable TV. It's amazing what these guys can do and you're left with a neat, invisible install. There's no cabling in any of my duct work, although in places ethernet runs right next to it, affixed to the duct with little plastic clamps. 

For various reasons, I don't use any equipment provided by my cable co/ISP. I choose my own equipment and contractors. (The sole exception is the little decoder box needed to receive local TV.)

For my system, nothing has bettered this wired network. It's been absolutely stable. No hiccups. Sounds great. No heroic measures required.

I stay away from long ethernet cable runs, longest is 1.5m. By having ISP modem located in listening room, no muss no fuss install, all cable runs short and sweet. Don't care about the long run of ethernet for the whole house router.

@jeffbij - 

Yes. 328 FEET. That is what I meant, NOT what I wrote. My bad.

As for the shielding, YES YES YES on the separate sheathing/conduit alongside the ductwork.