Honestly, for me, I try to vary it up sometimes. My first fort was, of course, just "Hey, I could probably fit a Trade Depot there" while I learned the rules, my second was a meticulously planned like 128x128 underground hotel of sorts with a completely hollow central area and random-but-kind-cool crosswalks, my third big attempt was a megaproject with distractions turned off where I more or less just dug away the whole first soil layer and tossed beds and stockpiles wherever. The dwarfs were more or less all legendary consolers, so complaints (which made up like the entireity of EVERY SINGLE DWARF's recent activity thing) were deflected. It varies.
A few forts later, I'm doing the meticulous planning thing again, trying to dig as little as possible so that when I remove constructions and finish my... rather 'ambitious' mining activities*, the whole thing will look like this wicked purely natural cavern - I'm even using an underground river just for having an underground woodsy area sort of thing, and collapsing a whole ton of soil layers a looong way down for an underground beach by my lake. My temp fort is living in a completely hollowed out mini mountain just isolated from the main mountain range, with a dwarf-dug moat around it that fills from the somewhat-nearby brook (rather than just pump it underground, I've been using the mouse-draw tool to get some nice random curves as the brook actually forks and makes its way lazily over). Of course, having very little floor space and refusing myself mining out unnecessary area just to put 'temp' rooms, I've been awkwardly building rooms upon rooms as migrants come. It's getting a bit weird-- to get from the food stockpile to one bedroom, you have to go through one room, up a staircase (in the room), out into the main hall on that floor, through another few connected rooms, down again, then up a few floors somewhere else.
Of course, "temporary" in this case refers to... what, the next ten-ish in game years worth of digging? When I do finally take all the temp stuff down it'll all be glorious and 'untouched'.
So it varies for me. You can do all-in-one shape and look cool, make it up as you go, plan it out to look really awesome or really intentionally natural... it's all good. Personally, as long as it's a fairly consistent style across a fort's entire layout, things should still look great.
* for those somewhat curious, I'm digging out roughly 50z of rock in a probably 2x4 embark-tile area. Tee hee.