Recommendations for PC -- for modest system --

Looking for recommendations for PC for a modest AV system -- I know all things audio are personal preference - but still want feedback on experiences with PCs under the the <$400ish mark - 

My meager system:

Marantz 7705
ATI 7ch x 200 amp
B&W CDM9NT x4 plus matching center

Budget - is low compared to many here - but still looking for some solid guidance - <$400 for each PC for amp and AVP. If I can spend less - that is ideal - Not looking to squeeze every last bit of sweetness from my AV system - just want something that is a balance between - far better than stock PCs -- and improves system overall - on the exponential curve of price vs performance.

Considering the following: 

Audioquest - one primary reason I am considering AQ - I can purchase at 45% msrp...
Madscientist - unfamiliar but seem a few here have exp with them... 
DIY?  -- Can I approach equal or better quality - for less if I DIY with the likes of with neo or dh cable or other with WG or other connectors... Is it worth the effort to DIY at budget I have set? 
Synergistic Research - considering - but I see none in the <$500 range... 

Thanks in advance.

Cullen, Audio Sensibility and Audio Envy are all great internet direct companies with good customer service.  In my current setup the Audio Envy power cables are doing a great job. His prices are well under your limit and he has a trial period. I have also owned PC's from the other two companies and they are in use in other systems around the house.
I followed advice from this forum and purchased a Synergistic Research Master Coupler X2 in 20A for my amplifier. Well I can tell you I am so glad I bought it, there is a difference with it in my system.
Oh, I purchased it used for about $500 from memory, + shipping.

I have been interested in the Mad Scientist - Nitro NANO Power Cord and I've been on Facebook with the manufacturer (I think the 10% discount is still current?). I have been using Mad Scientist - Heretical Digital Cable with KLE Silver Harmony Plugs, with favorable results. However a review of his USB still placed Curious Cables USB as better. (I used to build Curious Cables, solid annealed pure silver data wires in USB), so I'm still doing my due diligence.

The Inakoustik power cords and power conditioning certainly has my attention, and I am looking into them as well.

Keep an eye out for the Master Coupler used, if you don't for whatever reason like it, it'll hold it's value well. For me, I'm going the upgrade mentioned with Michael Stallone, and my MC X2, it's a dead set keeper!
Ice Age Audio. Most bang for the buck.
You'll only need 15A with that 7705 or virtually any SS AB or D amp. Not sure you'll hear any diff with an a/v rig.
Of course the bigger gauge wire to the outlet the better.
Good luck turning everything off.
You'll probably need a flashlight during the best SQ time portal.
You can buy AQ Monsoon Extreme 1M for $301.50 or 2M for $355.50.
These are Garth Powell engineered with silver on copper contacts.  They are one step below the level where the battery packs come in.  At your discount I don't see how anything will beat these, but I'm not basing on any listening tests, just the bare economics and the sterling rep AQ has for their newer power products...