I haven't read all the responses but here are a few that came to mind from our build a few years ago.
The wife really likes the central vac system and we got it with a few options, including a garage hose that I love and baseboard ports in the kitchen and salon (wife cuts hair).
If you want outlets under your eaves for Christmas lights, have them wired to a light switch in the house to easily turn them on and off. I went with a built in system that is always up and I can control with my phone for the Christmas lights but the light switch is a cheaper route.
Depending on the size of the house, a hot water circulation pump can be awesome. I get hot water to my shower in less than 2 seconds with it on, it takes about a full minute without the pump on.
If you have kids, suspended seating at the island, way nicer than dealing with bar stools.
Our cabinet company was testing out a new product idea and threw it in for free on our mantle. There are hidden cupboards behind most areas of the mantle. (See photos) They are kind of hard to access without knobs but it's pretty cool for hidden storage of things you won't use very often.
I have dual shower heads in my shower and I'm disappointed in the rain head. I need to try a different head but I don't like it nearly as much as the one my Dad has. Same brand too. I still like the idea, but I never use mine cause it doesn't work well.
LED lights were worth it.
Smart thermostat and doorbell were worth it to the wife.
I had the electrician add a floor plug where I knew our couch was going so the motors on the recliners can run without cords scattered all over the floor.
If I had to do it again I'd insulate the garage and add a floor drain.
My neighbor is building next door and added an RV dump in the corner of his huge garage tall enough for him to store his trailer inside. It's tied into the sewer lines so he never has to go to a dump station. That was a cheap idea I wish I would have thought of.
Alot you can do, just depends on what you want to spend and how the house lays out.