Considering I am cramming my shop into a 1980s undersized 2 car garage (18x20 with 8.5ft ceilings) I would make the thing bigger... Not stinking enormous, but bigger. I would LOVE a 24x32' shop with at least 10' Ceilings, 12' would be better!
Make sure the building is designed and built for heating / cooling efficiency as best as possible. Lots of insulation, radiant barriers and such. And include central heat / AC into the design. Folding, insulated coach doors, or a single slider instead of dual overhead doors. would be great, as would at least 200 amp electrical service, with 40 amps dedicated to 220V.
There are things I LIKE about my current setup that I would carry over. Those include using the wall rack setup for bench top type tools. Now having said that, If I had the space and money, I would upgrade to one of those Grizzly 12" planer / jointer machines so that would kill the need for 2 of them, and the bench grinder / sharpening station would be permanently mounted on a purpose built bench next to the lathe. All that would really leave is the Ridgid sander... Seems a lot less effective when you think of it that way I guess...
I would have a much bigger compressor, and compressed air piping through the shop, and easily twice as many shop lights...(twice the space, twice the light right?
And yes, a 3/4 bath (who wants to go back into the house smelling like sweat?) and a small beverage fridge are must haves if we are going into dream land. Of course the adult drinks stay in the fridge until the work with the tools is done for the day...
I would also like some sort of ruggedized notebook PC for viewing things like project plans and other misc ideas while in the shop, and a good 5.1 audio setup to go with it to drive some tunes as needed...
Trying to follow the example of the master...