Building a house

Room is the most important piece of the audio puzzle. Go out to expert sites like Cardas, Acoustic Fields, and read Jim Smith’s get better sound book. Room dimensions are forever so get them right in the beginning.
Pull multiple 20amp dedicated circuits to the areas you will be setting up your equipment (read job m smith’s book on this too).
Use wired Ethernet for your audio equipment and make sure you have good access to 5ghz wifi to use your ipad/iPhone to control your music app like Roon or others.

Maybe  a bit more than  you need...maybe not.
And a bit of a different problem
I'm an architect doing larger scale projects, namely Educational. Often the program involves a Music Room....an instructional music class for instruments. Sometimes to listen to recorded music  as well, but not always.
This is different from a home in that has to put up with a certain level of use that you won't experience.
The construction is meant to isolate the space from other adjacent spaces. I have  done suspended and isolated floor systems, as much to isolate it from adjacent spaces but also  from  the resonant nature of the structure.  Ceilings also are a special consideration with very specific suspension methods.
At the front of all of this are the room proportions

A great way to block sound transfer in addition to the the 2" x  6" staggered studs, is to put a layer of mass loaded vinyl between layers of drywall, or at least between the studs and drywall.  And it's not that expensive. 

Decide where your gear will reside and run in wall speaker wires to other rooms so can have many places to listen and compare not just one.
Also have all the walls and floor and ceiling, as applicable, of your main room insulated ( internal too not just external walls) and install solid wood doors not hollow there so you can have some volume at night and not disturb the family.
That’s what I did. Provides a lot of flexibility for enjoying your hifi in more rooms and any time of the day

Basalt!