If you had a particularly large home/mansion, what would be a uniquely designated room of your choice?

One with all those neat vending machines you see in Japan.

And one where all the taps were plumbed with different flavored juice. Connected to the cereal room of course.😃

I hope you call it then Kelloggium.

I'd have a room of requirement that is actually made of several rooms and spins around, so whenever you opened the door you wouldn't know what you'd find on the other side.

I would have an indoor outdoor room with lots of large skylight windows and it would have one whole wall which opens up to the outdoors.
I would have a place for some tropical birds, a large ensuite bathroom with a spa tub with skylight above it.
In the room itself I would have lots of bookshelves and books and a large bed.

I would have art rooms where I collect art and go around my gallery and admire it

If I had a larger house I would extend my home gym. A boxing ring would be nice, even a smaller one.

I would like a dance studio where I could lock myself away and relive my youth 😌

Meditation Room

I set up my bedroom like a bedroom/living room combo. Dont need most of the rooms in my house

I would have a designated meditation room. 🙏

Art studio/greenhouse