The answer is that this requires testing. My answer will be absolutely correct for some readers and wrong for some others. Not every component will react the same way with a given power cord. I think if you had only one shot at it, the best choice would be Purist Audio Dominus. It is very expensive, especially in the RS version. A less expensive choice that is excellent is the Siltec. If you want cheap and good, the old discontinued Tiffany TPC-60 is amazing, usually sells for about $50.00. It certainly will beat any stock cord by a mile, and provide a welcome and inexpensive improvement to less critical components in your system.
What AC Power Cord sounds best?
I'm looking to upgrade my power cords. I currently have 4 Synergistic Research AC Master Couplers in my system. They sound great but I understand there are some others out there with a quiter background, better bass, increase resolution, etc. Please let me know of your experiences with the 'really good stuff'. Thanks!