Spkr, interconects, or power cable upgrade first?

Power cords first, but if you do decide to change interconnects & speaker cables. I also second Paul Speltz anti ic's preferably terminated with Eichmann bullet plugs. His anti cables are also hard to beat price & performance wise if you're on a budget.

Would highly recommend Audio Art Cable PCs - IMO you will hear a difference at a moderate price

Power cords first. Better power delivery results in better sound from the source on down through the signal chain.

Power cords first, i/c's second, s/c's third, IMHO.

Cheers,
John

Not arguing with those advocating addressing power cords first. I do suspect benefits of the change will depend on which (PC, IC, SP) is the "weakest link" in the chain...that is, which is doing the most to limit or degrade signal generation or transfer. In my case, I doubt I'd have heard an improvement had I changed power cords prior to addressing speaker cables given their oxidized state. Maybe the generic answer is to change out that piece first that is furthest away from "state of the art" - or maybe make that furthest away from "best of the art" available with a specific budget.