Wiring
Having moved into a new house myself (1.5 years ago), I can certainly attest to the fact that you would want it to be wired up for whole home audio and the like. I can't give you much advice on hooking it up to your 3805 since I'm not as familiar with that receiver though I'm sure plenty of info is available in the manual.
Here are some thoughts that might help you in your endeavor. First off, if you use Apple computers or iTunes to any degree, you may be able to avoid most if not all of the wiring requirements for whole house audio. I know that the Airport Express is a great way to get clean audio (either by optical or analog connection) to a set of powered speakers. However, many people probably won't do this or want a true wired system.
In that case, I would draw up where you plan to have the speakers in your house and get an idea of how you want to distribute your music to them and by what means. Next, you'll need to plan out a number of things. The first being where the receiver(s) will be that are the source for your whole house audio setup, and the length of the runs you'll need to get your audio to the speakers. If you can, try to keep the receiver(s) located as central to the areas being wired as possible. Of course this is not always the case, but it does help in terms of wiring. The second thing I would do would be looking into running conduit in the walls and setting up wall plates and the "cans" for the speakers (I'm assuming they will be "in-wall" speakers). The conduit should be a significant size so that it can easily take larger diameter cables. Using a 1.5" PVC conduit pipe is pretty good for more than 90% of installations. It is easy to install (no soldering or anything like that) and cheap to use. Next, for long runs (people may constitute anything beyond 30 feet as a long run, but, I look at 20 feet or more myself), use a heavy-gauge wire. You can look at 10-guage or even combining two 16, 14, 0r 12 gauge wires for each connection to help you get larger surface area and maximum power transfer. The reason being that the farther you are from the source, the less power you retain due to the surface area of the wiring, so, make sure to beef up your wiring, especially if your receiver(s) are either 1) not too powerful, or 2) taking on a large load. Generally speaking, you don't have to worry about heavier gauge wiring if your receiver is simply sending the signal to satellite amplifiers using either stereo plugs, rca plugs, or ethernet cable. Still if the satellite amplifiers are far from the speakers, than the larger cable-requirement still applies.
One of the last things to do is ensure that your cables are properly terminated and connected inside the walls. You may require spades, banana plugs, etc. You'll want to use low-voltage wall boxes to house the incoming cables and cap them off with the proper wall plates. Just ensure that the cables are flexible and aren't making extremely sharp turns under pressure, this can crimp the cable or cut off some of the internal wiring.
I know it sounds like a lot to do, and trust me, it is. But you will certainly be happy with the results. If you can, trying performing the runs AFTER your plumbing, HVAC, and electrical systems are in place so that you don't interfere with their placement. I might also add that, if you have the capability to do it, see if you can put in a couple of dedicated 20-amp wall receptacles where you think you'll be plugging in your amplifier(s). This will allow you to getting a cleaner power source (though I would still recommend a line conditioner of some sort) and will ensure that you have a proper supply load that is unshared on that particular line. Just make sure to change the color of the face, plate, etc. so you know which outlet it is when you finish your drywall. I hope I haven't missed anything! Good luck!
