I didn't have the time to read all of the thread, so I'm sorry if my idea came up before.
I usually don't play for very long (I started out on an old computer with FPS <20, thought that was normal and sill getting used to the faster gameplay. Right now, I'm on a fort that's almost three years old and still going strong, with construction plans as follows:
I'll build several floors of wide-open space, (call them "Big Room"s if you must) designated as high-traffic and with nothing in them but pillars, statues, and (if I have to) stockpiles and dining rooms (which can become legendary with very little effort, given so much space). There will be multiple large stairways, each bigger than most of the "Stairs Of All Things" I've seen on this thread, but a given stair will only connect two floors together,
nothing else (if they strike platinum I send an engraver, not a miner). Everything else will be in (cramped) complexes connected by a multiple seperate stairwells to
ONE AND ONLY ONE of the great halls. Sleeping quarters will be where needed/availible, that is to say near workshops for craftsmen or
en masse for my workers.
Right now about 80% of dwarves in my fort are organized into two groups: Peons and Serfs. Both have hauling, wood-burning and architecture enabled (although I may later have a dedicated architect.). Peons also have mining, mechanics and furnace operating, plus carpentry and masonry for the sole purpose of wall-building/block making. Serfs (being less numerous than Peons) handle all the farming-group jobs, plus weaving, dyeing, and wood-cutting. Both Peons and Serfs are expected to serve in the military at need, though I am more likely to call on the former first, as well-trained miners already know how to weild a pick in battle. I haven't yet built an orginized military, but I plan on having at least one elite squad who train full-time in both crossbows and hammers and are always on duty. (See, I got all the traditional dwarven weapons handled: picks, axes, crossbows, and hammers.)
The idea behind this is that I can have everything be put in tightly up against each other, with no through traffic in the work space, and yet give my dwarves complete freedom of movement. Thus I get all the benifits of having no walls, without the chaotic clutter it usually entails.
Above ground, I plan on having a castle-type fortrification: First, a three-Z-level high wall, with the top level being a compleatly sealed rampart accessible only from one of the 5-story towers, which in turn are accessible only from underground tunnels connected to a central fort or to airlocks with located inside a special tower next to my gate that might possibly have some seige equipment as well, seeing as it's a civilian operated structure.
Above ground will be a few structures fortrifying the entrances underground- I embarked on an aquifer, but fortunately the map I got freezes every winter, so I wait until then to peirce through then reinforce with constructed walls. It's certainly not a
dwarfproof foolproof plan, (I've lost half a dozen dwarves to falling into channels they dug out that then flash-freeze) but I've already made one entryway and am well towards makeing a second, more conviniently placed one (which happens to re-use my failed first-ever attempt to get through an aquifer, but that was before I found out the map froze).