How do I design a home audio system?

Less crappy Slappy hit it right on the head. I do some work for a custom installer, including typing the occasional proposal, and your going to need at least $400 per room for a impedence match volume control and a pair of crappy speakercraft in-walls. You could get away with using a two zone receiver, like the ones from denon, but your going to have to add a few high current amps and a impedence matching speaker selector box. There's a company that makes a volume control with a built in amp (12 watts/ch?) that you could use. That way you would only have to run low level to the VC's (volume controls). However, in larger rooms, and outside, 12 watts aint gonna cut it. I think the amplified VC's run about $250 each. Anyway you look at it your going to spend around $6K to do 8 rooms/2 zones. What about IR repeaters to control the source from different rooms. What I would recomment, is that if you don't know what your doing, hire a professional. With labor and equipment you'll be lucky to spend under $10k this route but at least you will know it works. Better than spending a few grand and then having to call a pro to fix your mess. That's if they will even attempt to fix it.

Less crappy Slappy - I've seen whole house audio projects that were well over a Million. The crappy systems usually are in the $40K-$60K range. We did one house that was so big the TV delivery guys thought it was a hotel and drove around for an hour looking for the house. Finally they called on the cell and said that all they could find was a big hotel up on top of a hill. "Dude, that's not a hotel, that's the house...." That's a 42000 sq/ft house not including the 17 car garrage on 27 acres with a manmade private lake for fishing and water sports. We did another house were they spent a half mil just to add one room to the house for the home theater. When you add in the equipment, it was north of a million.

What kind of in-wall wiring would you guys recommend?

I've spent mucho bucks trying all types of wires for my main rig, but I was wondering what I could use to run through the walls into my Slappy Crapper.

Will the stuff AudioAdvisor work?

I may use outdoor speakers because they'll be more resistant to Crapper Stink.

I agree with S7Horton. Start with just a few rooms but set it up correctly.
1-If you want a system for just multiroom you still have to be careful with which receivers actually handle multiroom vs some that only have a line level output.
2-Do you want the ability to have different things on in different rooms?
3-How loud do you like it? Or,just background music.
4-For any real listening, you can probably find speakers for less than $200/pair but you get what you pay for. I've owned cheap in walls. Wow do they sound bad, echoey, crummy bass, etc...
My best advice for now, wire just the main rooms that will be used and put in/up good speakers. Buy a good impedance matching unit and hook up any source to see if it works. Yes, I actually melted a cheap impedance matching unit and finally bought a 12 zone niles.
My whole house system:
Anthem AVM-2 with multiroom
Denon DVD
100 disc cd changer
Dishnet satellite receiver with music channels
AMC 2445 90 watt/ch amp-I rarely use more than 2 pair of speakers at a time-so, I'm really not pushing the amp
Niles remote eyes(3)
Niles IRP 6
Niles IRP 2+
Niles RSL-6 impedance matching swithbox with 12volt triggers and remote on/off
3 Niles Intellipads where I don't want to use remotes
Various in wall/on wall speakers by Niles, Speakercraft, EV..... Need some in wall subs soon
Adcom line conditioner
About 1000 feet of 14 gauge wire
About 1000 feet of cat-5+ wire
Several universal remotes
This currently handles 5 rooms. I can/will add 2 more rooms for the cost of speakers and wire. Go price this and see what you are up against. Good luck for $1000.

Prpixel

Man that has gotta be fun. While i was in the military doing phone work i had to run my fair share of cables through some really crazy locations.
Man i enjoyed that work too.
I could only imagine how much fun i would have wiring up 500k-Mil+ systems. The only job that sounds more satisfying is the job that would afford one of those systems in yer own home.

Slappy,

I just program the home automation stuff. Too old, to beat up to do anything else. Most of these expensive systems use a lot of midfi equipment. Most of the money goes into making really easy to use and hiding the equipment. For the most part, people in this price range want it easy to use and don't want to see it. They can care less how it sounds.

In one install, a pair of Conrad-Johnson Synthesis reference speakers was buried in a cabinet over a RPTV. Had to lay the floor standing sats on thier sides and the two subs, which are about 6' high were also laying on their sides. In another system, a big pair of Duntechs were buried in a wall. Sacrilege!!!!

Have you had a chance to play around with the room EQ function on the Denon 3505 yet?