Most compatible speaker/interconnect and power cables with ARC ref system?

Nice system.  It deserves the best you can afford in the cabling department. 

I agree ... call ARC and find out what Warren uses in the listening evaluation room. 

In the meantime, call Ray at Von Gaylord Audio and talk to him about his cables. They're not cheap, but not the most expensive by any means. Ray's cables let the music flow with a natural, organic beauty. 

http://vongaylordaudio.com/beta/cabling/

Also ditto on the Synergistic Research Black fuses. AND ... you don't want to pass up trying their cables either. Their Level 3 PC's are truly a great product. 

http://highend-electronics.com/collections/synergistic-research

I've seen Shunyata, Sainline and Transparent at different times in the ARC listening rooms. Of course, that does not mean that others might not be better. I've tried Shunyata and Sainline cables and both are excellent with ARC. Service at both companies is outstanding. Of course, at Sainline--you deal directly with Chris Sain. I have not experimented with Transparent.

Thanks to all for the valuable advice - I will certainly replace the stock fuses. Is it best to choose one manufacturer for pc, interconnects and speaker cable (the whole is better than the sum of its parts type of argument) or should each component be tested one at a time and each one be judged on its merit?. Any further advise or any special deals you know of or could recommend for my system would be much appreciated!

To ME, it sounds like you don't really know what you want.  Here's a recommendation.....Call Paul at Clear Day cables.   He will send you his cables for audition....free of charge.  When listening you will have a base line of reference, for any other cables you might want to try.  ...I have had success with Audioquest, Kimber, and Wireworld.....  Remember all cables bring something different to your system.  The goal is to make you smile.  Re: Power cords.   In my estimation, power cords are the most important cable in my system.  I strongly suggest you make your own.....Get top of the line Furutech, or Oyeida IEC and wall plugs, and in 10 minutes you will have power cords as good (probably better) than any commercial cord.  Touch base with VH Audio for the parts and for his recommendation..good guidance.

Is it best to choose one manufacturer for pc, interconnects and speaker cable (the whole is better than the sum of its parts type of argument) or should each component be tested one at a time and each one be judged on its merit?

This is a common question, which will always provide controversy. Ultimately, you pay your money, so you will have to answer this question for yourself.

I know some folks who have had success running all the same brand of cables/cords. That has never worked for me though, and I have tried a LOT of cables cords.
For me it seems that the more I get of one brand, the more I become aware of the flaws of that particular cable line.
I have had better success balancing the sound to my tastes by mixing and matching.

Good luck.