Details on wiring my house for sound

Jp that box should do you fine; congrat's on picking fuses over breakers. Those Fusestat's are actually resettable screw-in breakers; notice the small pop-out in the center for resetting when they trip. There are OK for non-audio loads but use real fuses (not glass body) for the sound system.
Those socket contacts are apparently plated with something; not to be concerned (whatever it is) they built the box & specify copper wire only so they know what they're all about.

Bob,

Thanks for your post. My fusestats are actually fuses and not breakers, but I won't use them anyway.

Umm.. just happened to browse this post, and could use some info. I have a dedicated circuit for my audio recepticles, in my Square D breaker box.. and was going to go further and create a dedicated subpanel for audio.. are you saying breakers are noticeable worse then fuses for audio?

Not sure what you have there then? Maybe these are time-delay fuses vs. fast fuses? Time delay elements look somewhat more complicated than the fast-blow types, they usually have a spring & some other stuff in there. They are intended for motor applications (refrigerators, washers, dryers, furnaces, etc) where the motor's startup current surge would fail a fast-blow element. I recall time delay fuses being called Fusetron's sometimes. I have not compared these to standard fuses when used for audio, but they might be OK.
An alternative approach when fusing a motor device is to overfuse it so the surge current won't fail the element, but this offers poor protection. Similarly, fusing a non-reactive load with a slow-blow fuse offers poor protection but it might, still just sound fine.
I only advise against glass body fuses because they sounded not that good in my own experience. Ceramic is definitely good (if you can find them anymore - please grab a couple boxes for me if you do find 20 amp ceramic fast fuses). Lately I've beenusing the nerw plastic body fuses but haven't yet made any hard comparisons against the one ceramic fuse that I still have left.

Yes Queg that is a fact. There are a number of archived threads about this; please try using the forum search engine. If you come up empty then post back here again; I can find some of them for you from my personal archives.
Here's a recent one: there was a fair amount of contention & argument from those who refuse to believe this, but have a read-through, try it for yourself, & post back with your own experiences.
http://forum.audiogon.com/cgi-bin/fr.pl?htech&1012281942&read&keyw&zzceramic=fuse

Bob,

Yes, mine have the spring in them and are slow blow. I'm going to remove them and go with regular fuses. I will search for ceramic 20 amp fuses (my 84 year old dad may have some as he has a fuse panel). Anybody else got a source?

Found regular, slow-blow, ceramic fuses at Home Depot today! Bought a box, but the guy said they stocked them all the time.