Here are a few trends / ideas that occur to me (and we are implementing):
- There's a long term trend toward low voltage lighting. Consider this as you do your system design. I'm putting a lot of low-voltage drivers in the mechanical room rather than routing 120V to every fixture.
- Depending on where you live, heat pumps rather than furnaces and A/C might make sense. We're doing hydronic heating in the floors, for instance.
- Solar and geothermal as sources of energy.
- We're doing a Passive House - inspired but not certified - construction, so we're doing a lot of work about controlling movement of air, humidity, bulk water, and heat. This requires "new" mechnicals like heat recovery ventilators and make-up air systems.
- We're doing a snow melt system for the front porch and near the garage entrance. Might be great... others think it's nuts.
- For energy storage on site (batteries), I'm setting up critical loads and non-critical loads. That's not hard to imagine, but one thing that might not be obvious is that I'm putting one critical load receptacle in every room. The concept is that I'm not smart enough to think of every critical load and this might give us a plan B after the drywall is all up.
- There is little question that with today's tech, wired ethernet is faster than wireless. But the state of the art keeps improving and I'm debating about whether it is really necessary to pull CAT5 or CAT6 or CAT26 everywhere. However, wireless access points are not all the same thing in different gray boxes. I've been very impressed with the Ubiquiti products in other settings.
- I've been underwhelmed with whole house audio/video systems for the price. Google Home (and other products like it) provide a decent experience and can be coordinated around the house. We're not super high fidelity audiophiles, so others may push you in another direction. I like the visual of the Sonos In-Wall speakers.
- We're going to use the Lutron lighting automation system. I have tried every lighting automation system (small exaggeration) trend from the old DC-switched relays, to X10, to SmartHome, to you name it. None quite match the reliability of Lutron. I'd really like to use their Homeworks system but they only make that available to their distributors to manage, so I'll be using Radio Ra 3 as the controller.
- For lighting design, I've been impressed by the work posted all over youtube on lighting activities rather than lighting the center of the room itself. Dropping in a bunch of can lights everywhere will probably work, but is not optimal, I'm learning. Also, pay attention to the options to match color temperature to time-of-day so that you're not stuck at 1700°K nor 4000°K. [Exaggeration intended.]
- If you're not putting in EV chargers, you may want to consider that, for resale value even if you won't use it yourself.
Those are just a few ideas randomly selected.
I'm a master electrician (Wisconsin), and we're building the house ourselves as a retirement project. If you want to follow-along, we're doing a daily Instagram update:
https://www.instagram.com/betterhouseproject/. This is not a best-practice or instructional video series... mostly just a public diary of our experience. We have huge respect for all the trades that we're learning along the way.
- Paul
I've seen whole house sound systems, I don't have experience in them, but they don't seem overly complicated. Volume control in rooms and speakers in the ceilings. 
