What I understood from the whole power story, is that it's about a few things:
1. Stable power. Is your voltage around 110/120V constant, or does it drop and rise by a few volts. Power peaks can wreck electronics, so a surge protector is key here.
2. Clean block wave AC. This is where the problem lies and noise occurs. You can remove a lot of it with better cables and noise filters, but ideally you have a system to regenerate a clean block wave.
I use a PS Audio system to do the latter.
Once your power is "clean" (so from the regenerator outlet), keep it that way with high end cables.
I'm not a super expert on the topic, but this is what I got from researching it a while ago. Happy to hear others' opinion.
I'm not far from Seattle as well, if the OP wants to come look at the PS Audio.