Drop some chain cups in the floor. you might never have to straighten a frame, but they come in darn handy for other things, too (I don't have, but a friend does).
Level floor, as good as you can get it. Whether building furniture or bumpers, helps to have a level foundation to work off of.
I did 10' ceilings...assume that's what you mean (not a 10' boat)
Go 12-14' if you might ever do a 2 post lift. I did 2' masonry wall with 8' stud wall on top.
Lots of outlets. And lights.
Doors...a 16' rollup door is really a single car door. My doors are 9'...still pretty close when backing in a trailer, or the mirrors on my F250. I'd go single 12' doors next go-round.
If you have enough lot, make one bay drive-through. (Bay doors on both sides of building.
My next shop will have a separate welding bay. Too much clutter and stuff in the main area to weld inside now. A separate welding bay (or at least a room) would be great.
Try and avoid posts altogether, but figure in at least one beam overhead, even if you have to pop in a post, for a chainfall.
Air compressor in an insulated closet (best if open to outside) for quiet.
Definitely a half-bath. (Or at least a sink (same thing for the guys)).
Shed roof, 10-12' on at least 2 sides....so all your collected junk and parts can get under cover.
Carport or overhang on front, so you can work outside and keep cool/dry.
AC and Heat. Really...my next shop will definitely have it.