Power cable Advice...

Audioquest Thunder and up the Audioquest line from there.  I have two different brands of PCs in my system (Audioquest and JPS Labs).  I have JPS Labs speaker cables and Audioquest interconnects.  They all work together to create pure magic. 

@megabyte 

A more serious answer. 
 

This is a video of an interview with the founder of Shunyata. At about 10 - 11 minutes he starts going over what a power grid is and does. This should help.
 

If you have all the money that you want/need, go ahead and blow whatever you want on power cables.  But it doesn't seem that you are in that category.  I have a Pass 250.8, ARC REF 6 and Sabrina X speakers.  In my system, I have heard a decent, audible improvement in the bass when switching from stock to an upscale PC.  By no means is it a "blow me away" difference, but it was certainly an improvement.  Is the minor improvement worth $5k, 10K or more?  Certainly not to me.  I have had Morrow MAP 3 PC's, Audience PowerChords and ultimately, Shunyata Alpha v.1 and V.2.  The difference between Stock and the Audience cables was noticeable.  The difference between the Audience and Shunyata (on my MSB DAC and Pass amp) was not, or barely.  An Audience on my REL s/510 v. stock was not noticeable at all.  The biggest difference that I noticed was replacing the ARC stock PC with a Shunyata Alpha v.2, which was a noticeable improvement.  My advice: don't buy into the hype. Purchase used, and stick to the <$1500 used market.  I'm sure that, depending on your system, there may be a difference between the Shunyata Alpha's and Sigma's for example, but whether that minor difference is worth the $$$$ is a judgment call only you can make.  I highly recommend the Shunyata Alpha's and a sweet spot in the used PC market.  I'm very happy with them.

That's a pretty big jump from stock and quite a large budget dedicated to AC cables.  Just something to think about is that you can make your own cables for a fraction of the cost and have more control over experimentation with what works best for your system.  There are endless debate on plating materials, cable design and even shielding (such as whether to ground at one end or both).

As an example, Supra's SPC 2.5 cable (silver plated copper) terminated with IeGO's gold plated copper plugs and shielding grounded to the mains side is an excellent cable and will be a tangible improvement over stock.  Material costs are maybe $150, at best.  Heck, you can even start with Viborg's plugs and see the different effects first.  If you like the combo, you can go all-in on more exotic cables and plugs.  Personally, I opted to add voltage regulation/power conditioning over pre-made exotic cables and happy with the results.

You cannot do better at ANY price than a Cerious Tech Lumniscate cable. it runs about $1599 but there are deals from time to time - particulate if purchasing multiple cables. Lumniscate cables complete transformed my stem and were if particular benefit with my digital gear and preamplifier. You will thank me later. A hidden "gem in the rough."