Wire the House A/C or get Power Conditioner?

Sorry, I will give you just the opposite advice. Always start by first running dedicated AC lines in a single home run pull from your circuit panel to each receptacle. Keep the cables as close to the same lengths as possible. Upgrade each receptacle to a high quality all brass/copper alloy, non-plated, 20 amp receptacle like Hubbell 5362 or 8300, Portport (a cryo'd Hubbell), or Synergistic Research TeslaPlex (best, most expensive).

Only once you have good AC coming to your equipment is it worth experimenting with power conditioners.
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You can carry this to any extreme of excess you're inclined to pay for. In my experience doing this three different times in different houses, you'll get very good improved results by using a standard 10ga solid copper wire. The biggest improvements will come from

- pulling direct home runs from the breaker panel (no intervening breaks or splices),

- using a separate home run cable for each receptacle,

- having your electrician apply Walker Audio Extreme SST contact enhancer on each connecton from the breaker to the receptacle (not kidding here),

- having the electrician clean and tighten the connections at the grounding rod and at grounding bar inside the circuit box, and if there is any question about the grounding rods, driving new replacement copper clad grounding rods, and

- installing cryo'd Porter Ports or Synergistic Research TeslaPlex receptacles. If you can install non-ferrous boxes for the receptacles, do this too.
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Agree you should use 10ga wire, and yes some electricians may grumble a bit.

As to installing isolated ground circuits and receptacles, I've become convinced that in residential construction with wood stud walls, or solid masonry, isolated grounds do not add any benefit.

Isolated grounds are used in commercial construction because of the metal studs in all the walls makes the entire structure one big grounding grid with lots of potential for adding multiple ground loops and noise.

This is simply not an issue with outlet boxes nailed to wood studs. In the residential construction setting, the single home run pull of cable back to the circuit panel makes for a single "isolated" ground wire connection. (But if your walls are built with metal studs, by all means use an isolated ground wiring installation and receptacles.)
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Saki70, as explained by an Audiogon member who is an electrician in another Audiogon thread several years ago (that I can't find now), what the isolated ground does is prevent the ground from being connected to the chassis of the receptacle. With both isolated ground and a non-isolated ground installations, the ground comes back to exactly the same place on the bus bar of the breaker panel. The only difference is in whether the ground is connected to the chassis of the receptacle.

If the receptacle and enclosing outlet box are attached to metal studs in commercial construction, the chassis is now making contact with the metal stud and hence to the rest of the building structure. With the ground being connected to the chassis (not isolated), your ground is now connected to the entire building structure. That can make for all sorts of noise, interference and hum possibilities. So, in commercial construction, you'd absolutely want to isolate the ground from the chassis: i.e., use an isolated ground receptacle and wiring installation.

On the other hand, in wood stud construction, the outlet and chassis are nailed to the non-conductive wood stud. There is nothing from which you need to isolate the ground. It no longer matters that the ground wire is not isolated from the chassis of the receptacle.

There is one other possible factor and that is the possibility of the fourth wire in the isolated ground installation providing some EFI drain or shielding for the length of cable back to the circuit panel. I don't know about that contention. I think you'd be better served by taking the trouble to twist the wires which make up the cable if you're trying to get maximum EFI rejection along the length of the cable.
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Hi Saki70, I don't consider you being argumentative at all. You're asking good questions and this is a confusing topic.

I'm starting from the assumption that one will be following standard code installations as provided in most jurisdictions in the U.S., so pardon me being a bit parochial in my assumptions. "Code" requires the ground and neutral to be bonded to to a single common ground at the circuit panel and then to the grounding rod. What you describe does not match "Code" as I understand it, but I'm no expert.

In my last home, I had a commericial electrical company that understood hospital grade installations do the re-wiring of my circuit panel and install isolated ground outlets and cabling. They did so and the grounding at the panel was exactly as I described above: bonded to a common point at the circuit panel and then to the grounding rod.
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Hi Saki70, the issue of installing a second and separate ground in a household system has been discussed extensively in the forums. Some knowledgeable contributors say doing so violates Code and creates a potential for a dangerous situation. Others say its the best way to improve your sound. From what I've read, I'll not do it. Bottom line, if you had a licensed electrician make the installation and the electrician got the work inspected and approved, it must be okay in your locale. If the work was not inspected...

For those who are looking for more information about the installation of a separate ground for the audio system, here's a thread with more discussion:

http://forum.audiogon.com/cgi-bin/fr.pl?htech&1193750975&openfrom&1&4#1

I recommend paying particular attention to the contributions from Gs5556 and Jea48 .

And this is all I know on the topic, so I won't be able to carry this any further - just offering the caution because so many audiophiles have gotten carried away on this isolated ground topic, and I find the potential for danger pretty frightening.
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Abbeydog, I gave you links to two sources of cryo'd receptacles in an earlier post to this thread before we wondered away from your topic. Here it is:

- installing cryo'd Porter Ports or Synergistic Research TeslaPlex receptacles. If you can install non-ferrous boxes for the receptacles, do this too.