The above post is dead on... Your budget determines everything, and if your budget is high, then what you want determines everything.
My home has about 17 separate zones of audio in it, each one can be independently turned on and off and has access to up to 16 different sources. All of these are completely independent zones of audio. Several of the zones have video as well, and likewise, they are completely independent of the other rooms.
So, my kids can watch a media player in the playroom, my wife can watch cable 1 upstairs in the master bedroom, and I can be in the basement watching the game on cable 2.
Meanwhile, my dad can be sitting out back on the porch listening to music on XM radio.
It's pricey, but works well.
In this case ALL the gear is in a specifically picked place in the basement which has plenty of cooling to it so the gear doesn't overheat.
MOST COMMON MISTAKE: Picking some stupidly small area to run the wiring to. You MUST put gear in to use, and it generates a lot of heat and can make noise. Heat is the #1 killer of electronics, and you don't want to pack stuff in.
Wireless is basically a myth. You need to power speakers, so you need to get wires to all the locations they are going. I would pick a good spot in the basement (under the stairs maybe?) and put the equipment there in a cabinet that can handle all the gear, and make sure the space has plenty of ventilation. Add fans to the space if necessary.
You can go wireless for control if you buy the right gear. Sonos offers some very good wirelessly controlled product. Other manufacturers do as well. But, it requires you to pull out your iPhone, or Android, turn it on, open the application, and use it. Not really as convenient as walking into a room and pressing the button on the wall that says 'XM' right on it.
But, this is still ALL about money, and the most important thing you can do right now is prewire and pick a really good location for equipment that has room to grow and gets plenty of ventilation.
Speak to an A/V professional in your area if you can, and be realistic with your budget. It is easy to spend $20,000 or more on a better level version of this system.