How much flexibility do you have in what you are building? (I've been away for 20 years and just getting back; so what I'm saying here is just what would make *me* happy and only my opinion.) I'm quite happy for people to disagree, and maybe I'll learn something.
If I were going to build the ultimate shack, it would be long and narrow...probably about 10 feet wide and 20 feet long. I would want windows along the long side (but high) near the top of the wall...not behind the equipment. I would want a nice (more normal) window on the far narrow (short) wall...and no windows behind me.
I would want a built in desk that went all the way along the long wall, and I would want to put much thought into some custom shelves that had plenty of ventilation (maybe even silent fans) that ran along the back of the custom desk.
I would fashion it to have a keyboard tray in the center, and a place for a monitor. I would also build in UPS supplied power to each of the shelves. I would like to have a natural gas generator on an auto-throw switch backing up the shack...so I would work emergency situations. I would make the back of the shelves on the desk have wire management.
I would want hardwood floors so my chair could roll along the entire desk. One end of the desk would be a test bench...with extra power and high shelves / table so I could stand and put something on the test bench.
As long as I was at it I would sound proof the walls and have a door that seals...that way I could turn the speakers up and not bother anyone...and not have to wear headphones. However, that would present a stale-air problem (and heat/cold) so I would want to make sure the room had adequate supply and return.
I would want some kind of sound proofing (like what they use in recording studios) on the walls...so my voice doesn't echo when talking
I would want some kind of shelves along the wall behind me.
Finally, I would want an ON AIR sign on the outside wall near the door.
When I really start dreaming, I would want a video security system so I could see the outside of the house (including the antenna farm) from the shack...but I don't want to get too unrealistic in my shack-dream...